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s390/cpum_sf: Dynamically extend the sampling buffer if overflows occur
Improve the sampling buffer allocation and add a function to reallocate and increase the sampling buffer structure. The number of allocated buffer elements (sample-data-blocks) are accounted. You can control the minimum and maximum number these sample-data-blocks through the cpum_sfb_size kernel parameter. The number hardware sample overflows (if any) are also accounted and stored per perf event. During the PMU disable/enable calls, the accumulated overflow counter is analyzed and, if necessary, the sampling buffer is dynamically increased. Signed-off-by: Hendrik Brueckner <brueckner@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
This commit is contained in:
Hendrik Brueckner
Martin Schwidefsky
parent
257608fb41
commit
69f239ed33
@ -49,6 +49,10 @@ extern unsigned long perf_misc_flags(struct pt_regs *regs);
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#define PERF_CPUM_SF_MAX_CTR 1
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#define PERF_EVENT_CPUM_SF 0xB0000UL /* Raw event ID */
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#define REG_NONE 0
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#define REG_OVERFLOW 1
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#define OVERFLOW_REG(hwc) ((hwc)->extra_reg.config)
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#define SFB_ALLOC_REG(hwc) ((hwc)->extra_reg.alloc)
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#define TEAR_REG(hwc) ((hwc)->last_tag)
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#define SAMPL_RATE(hwc) ((hwc)->event_base)
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@ -17,6 +17,8 @@
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#include <linux/percpu.h>
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#include <linux/notifier.h>
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#include <linux/export.h>
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#include <linux/mm.h>
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#include <linux/moduleparam.h>
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#include <asm/cpu_mf.h>
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#include <asm/irq.h>
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#include <asm/debug.h>
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@ -26,34 +28,54 @@
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* At least one table is required for the sampling buffer structure.
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* A single table contains up to 511 pointers to sample-data-blocks.
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*/
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#define CPUM_SF_MIN_SDBT 1
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#define CPUM_SF_MIN_SDBT 1
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/* Minimum number of sample-data-blocks:
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* The minimum designates a single page for sample-data-block, i.e.,
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* up to 126 sample-data-blocks with a size of 32 bytes (bsdes).
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/* Number of sample-data-blocks per sample-data-block-table (SDBT):
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* The table contains SDB origin (8 bytes) and one SDBT origin that
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* points to the next table.
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*/
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#define CPUM_SF_MIN_SDB 126
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#define CPUM_SF_SDB_PER_TABLE ((PAGE_SIZE - 8) / 8)
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/* Maximum number of sample-data-blocks:
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* The maximum number designates approx. 256K per CPU including
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* the given number of sample-data-blocks and taking the number
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* of sample-data-block tables into account.
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/* Maximum page offset for an SDBT table-link entry:
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* If this page offset is reached, a table-link entry to the next SDBT
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* must be added.
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*/
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#define CPUM_SF_SDBT_TL_OFFSET (CPUM_SF_SDB_PER_TABLE * 8)
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static inline int require_table_link(const void *sdbt)
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{
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return ((unsigned long) sdbt & ~PAGE_MASK) == CPUM_SF_SDBT_TL_OFFSET;
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}
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/* Minimum and maximum sampling buffer sizes:
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*
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* Later, this number can be increased for extending the sampling
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* buffer, for example, by factor 2 (512K) or 4 (1M).
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* This number represents the maximum size of the sampling buffer
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* taking the number of sample-data-block-tables into account.
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*
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* Sampling buffer size Buffer characteristics
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* ---------------------------------------------------
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* 64KB == 16 pages (4KB per page)
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* 1 page for SDB-tables
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* 15 pages for SDBs
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*
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* 32MB == 8192 pages (4KB per page)
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* 16 pages for SDB-tables
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* 8176 pages for SDBs
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*/
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#define CPUM_SF_MAX_SDB 6471
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static unsigned long __read_mostly CPUM_SF_MIN_SDB = 15;
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static unsigned long __read_mostly CPUM_SF_MAX_SDB = 8176;
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struct sf_buffer {
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unsigned long sdbt; /* Sample-data-block-table origin */
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unsigned long *sdbt; /* Sample-data-block-table origin */
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/* buffer characteristics (required for buffer increments) */
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unsigned long num_sdb; /* Number of sample-data-blocks */
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unsigned long tail; /* last sample-data-block-table */
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unsigned long num_sdb; /* Number of sample-data-blocks */
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unsigned long num_sdbt; /* Number of sample-data-block-tables */
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unsigned long *tail; /* last sample-data-block-table */
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};
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struct cpu_hw_sf {
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/* CPU-measurement sampling information block */
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struct hws_qsi_info_block qsi;
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/* CPU-measurement sampling control block */
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struct hws_lsctl_request_block lsctl;
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struct sf_buffer sfb; /* Sampling buffer */
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unsigned int flags; /* Status flags */
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@ -64,12 +86,23 @@ static DEFINE_PER_CPU(struct cpu_hw_sf, cpu_hw_sf);
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/* Debug feature */
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static debug_info_t *sfdbg;
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/*
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* sf_disable() - Switch off sampling facility
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*/
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static int sf_disable(void)
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{
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struct hws_lsctl_request_block sreq;
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memset(&sreq, 0, sizeof(sreq));
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return lsctl(&sreq);
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}
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/*
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* sf_buffer_available() - Check for an allocated sampling buffer
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*/
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static int sf_buffer_available(struct cpu_hw_sf *cpuhw)
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{
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return (cpuhw->sfb.sdbt) ? 1 : 0;
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return !!cpuhw->sfb.sdbt;
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}
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/*
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@ -77,32 +110,32 @@ static int sf_buffer_available(struct cpu_hw_sf *cpuhw)
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*/
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static void free_sampling_buffer(struct sf_buffer *sfb)
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{
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unsigned long sdbt, *curr;
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unsigned long *sdbt, *curr;
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if (!sfb->sdbt)
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return;
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sdbt = sfb->sdbt;
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curr = (unsigned long *) sdbt;
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curr = sdbt;
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/* we'll free the SDBT after all SDBs are processed... */
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/* Free the SDBT after all SDBs are processed... */
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while (1) {
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if (!*curr || !sdbt)
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break;
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/* watch for link entry reset if found */
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/* Process table-link entries */
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if (is_link_entry(curr)) {
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curr = get_next_sdbt(curr);
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if (sdbt)
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free_page(sdbt);
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free_page((unsigned long) sdbt);
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/* we are done if we reach the origin */
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if ((unsigned long) curr == sfb->sdbt)
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/* If the origin is reached, sampling buffer is freed */
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if (curr == sfb->sdbt)
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break;
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else
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sdbt = (unsigned long) curr;
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sdbt = curr;
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} else {
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/* process SDB pointer */
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/* Process SDB pointer */
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if (*curr) {
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free_page(*curr);
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curr++;
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@ -111,10 +144,106 @@ static void free_sampling_buffer(struct sf_buffer *sfb)
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}
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debug_sprintf_event(sfdbg, 5,
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"free_sampling_buffer: freed sdbt=%0lx\n", sfb->sdbt);
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"free_sampling_buffer: freed sdbt=%p\n", sfb->sdbt);
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memset(sfb, 0, sizeof(*sfb));
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}
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static int alloc_sample_data_block(unsigned long *sdbt, gfp_t gfp_flags)
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{
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unsigned long sdb, *trailer;
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/* Allocate and initialize sample-data-block */
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sdb = get_zeroed_page(gfp_flags);
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if (!sdb)
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return -ENOMEM;
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trailer = trailer_entry_ptr(sdb);
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*trailer = SDB_TE_ALERT_REQ_MASK;
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/* Link SDB into the sample-data-block-table */
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*sdbt = sdb;
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return 0;
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}
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/*
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* realloc_sampling_buffer() - extend sampler memory
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*
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* Allocates new sample-data-blocks and adds them to the specified sampling
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* buffer memory.
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*
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* Important: This modifies the sampling buffer and must be called when the
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* sampling facility is disabled.
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*
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* Returns zero on success, non-zero otherwise.
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*/
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static int realloc_sampling_buffer(struct sf_buffer *sfb,
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unsigned long num_sdb, gfp_t gfp_flags)
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{
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int i, rc;
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unsigned long *new, *tail;
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if (!sfb->sdbt || !sfb->tail)
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return -EINVAL;
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if (!is_link_entry(sfb->tail))
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return -EINVAL;
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/* Append to the existing sampling buffer, overwriting the table-link
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* register.
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* The tail variables always points to the "tail" (last and table-link)
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* entry in an SDB-table.
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*/
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tail = sfb->tail;
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/* Do a sanity check whether the table-link entry points to
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* the sampling buffer origin.
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*/
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if (sfb->sdbt != get_next_sdbt(tail)) {
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debug_sprintf_event(sfdbg, 3, "realloc_sampling_buffer: "
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"sampling buffer is not linked: origin=%p"
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"tail=%p\n",
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(void *) sfb->sdbt, (void *) tail);
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return -EINVAL;
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}
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/* Allocate remaining SDBs */
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rc = 0;
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for (i = 0; i < num_sdb; i++) {
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/* Allocate a new SDB-table if it is full. */
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if (require_table_link(tail)) {
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new = (unsigned long *) get_zeroed_page(gfp_flags);
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if (!new) {
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rc = -ENOMEM;
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break;
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}
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sfb->num_sdbt++;
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/* Link current page to tail of chain */
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*tail = (unsigned long)(void *) new + 1;
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tail = new;
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}
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/* Allocate a new sample-data-block.
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* If there is not enough memory, stop the realloc process
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* and simply use what was allocated. If this is a temporary
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* issue, a new realloc call (if required) might succeed.
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*/
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rc = alloc_sample_data_block(tail, gfp_flags);
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if (rc)
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break;
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sfb->num_sdb++;
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tail++;
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}
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/* Link sampling buffer to its origin */
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*tail = (unsigned long) sfb->sdbt + 1;
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sfb->tail = tail;
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debug_sprintf_event(sfdbg, 4, "realloc_sampling_buffer: new buffer"
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" settings: sdbt=%lu sdb=%lu\n",
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sfb->num_sdbt, sfb->num_sdb);
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return rc;
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}
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/*
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* allocate_sampling_buffer() - allocate sampler memory
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*
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@ -128,75 +257,74 @@ static void free_sampling_buffer(struct sf_buffer *sfb)
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*/
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static int alloc_sampling_buffer(struct sf_buffer *sfb, unsigned long num_sdb)
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{
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int j, k, rc;
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unsigned long *sdbt, *tail, *trailer;
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unsigned long sdb;
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unsigned long num_sdbt, sdb_per_table;
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int rc;
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if (sfb->sdbt)
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return -EINVAL;
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/* Allocate the sample-data-block-table origin */
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sfb->sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL);
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if (!sfb->sdbt)
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return -ENOMEM;
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sfb->num_sdb = 0;
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sfb->num_sdbt = 1;
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/* Compute the number of required sample-data-block-tables (SDBT) */
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num_sdbt = num_sdb / ((PAGE_SIZE - 8) / 8);
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if (num_sdbt < CPUM_SF_MIN_SDBT)
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num_sdbt = CPUM_SF_MIN_SDBT;
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sdb_per_table = (PAGE_SIZE - 8) / 8;
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/* Link the table origin to point to itself to prepare for
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* realloc_sampling_buffer() invocation.
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*/
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sfb->tail = sfb->sdbt;
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*sfb->tail = (unsigned long)(void *) sfb->sdbt + 1;
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debug_sprintf_event(sfdbg, 4, "alloc_sampling_buffer: num_sdbt=%lu "
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"num_sdb=%lu sdb_per_table=%lu\n",
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num_sdbt, num_sdb, sdb_per_table);
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sdbt = NULL;
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tail = sdbt;
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for (j = 0; j < num_sdbt; j++) {
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sdbt = (unsigned long *) get_zeroed_page(GFP_KERNEL);
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if (!sdbt) {
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rc = -ENOMEM;
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goto allocate_sdbt_error;
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}
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/* save origin of sample-data-block-table */
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if (!sfb->sdbt)
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sfb->sdbt = (unsigned long) sdbt;
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/* link current page to tail of chain */
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if (tail)
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*tail = (unsigned long)(void *) sdbt + 1;
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for (k = 0; k < num_sdb && k < sdb_per_table; k++) {
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/* get and set SDB page */
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sdb = get_zeroed_page(GFP_KERNEL);
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if (!sdb) {
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rc = -ENOMEM;
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goto allocate_sdbt_error;
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}
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*sdbt = sdb;
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trailer = trailer_entry_ptr(*sdbt);
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*trailer = SDB_TE_ALERT_REQ_MASK;
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sdbt++;
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}
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num_sdb -= k;
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sfb->num_sdb += k; /* count allocated sdb's */
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tail = sdbt;
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}
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rc = 0;
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if (tail)
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*tail = sfb->sdbt + 1;
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sfb->tail = (unsigned long) (void *)tail;
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allocate_sdbt_error:
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if (rc)
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/* Allocate requested number of sample-data-blocks */
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rc = realloc_sampling_buffer(sfb, num_sdb, GFP_KERNEL);
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if (rc) {
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free_sampling_buffer(sfb);
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else
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debug_sprintf_event(sfdbg, 4, "alloc_sampling_buffer: "
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"realloc_sampling_buffer failed with rc=%i\n", rc);
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} else
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debug_sprintf_event(sfdbg, 4,
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"alloc_sampling_buffer: tear=%0lx dear=%0lx\n",
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sfb->sdbt, *(unsigned long *) sfb->sdbt);
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"alloc_sampling_buffer: tear=%p dear=%p\n",
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sfb->sdbt, (void *) *sfb->sdbt);
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return rc;
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}
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static int allocate_sdbt(struct cpu_hw_sf *cpuhw, const struct hw_perf_event *hwc)
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static void sfb_set_limits(unsigned long min, unsigned long max)
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{
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CPUM_SF_MIN_SDB = min;
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CPUM_SF_MAX_SDB = max;
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}
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static unsigned long sfb_pending_allocs(struct sf_buffer *sfb,
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struct hw_perf_event *hwc)
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{
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if (!sfb->sdbt)
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return SFB_ALLOC_REG(hwc);
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if (SFB_ALLOC_REG(hwc) > sfb->num_sdb)
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return SFB_ALLOC_REG(hwc) - sfb->num_sdb;
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return 0;
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}
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static int sfb_has_pending_allocs(struct sf_buffer *sfb,
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struct hw_perf_event *hwc)
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{
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return sfb_pending_allocs(sfb, hwc) > 0;
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}
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static void sfb_account_allocs(unsigned long num, struct hw_perf_event *hwc)
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{
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/* Limit the number SDBs to not exceed the maximum */
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num = min_t(unsigned long, num, CPUM_SF_MAX_SDB - SFB_ALLOC_REG(hwc));
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if (num)
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SFB_ALLOC_REG(hwc) += num;
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}
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static void sfb_init_allocs(unsigned long num, struct hw_perf_event *hwc)
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{
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SFB_ALLOC_REG(hwc) = 0;
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sfb_account_allocs(num, hwc);
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}
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static int allocate_sdbt(struct cpu_hw_sf *cpuhw, struct hw_perf_event *hwc)
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{
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unsigned long n_sdb, freq;
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unsigned long factor;
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@ -225,19 +353,125 @@ static int allocate_sdbt(struct cpu_hw_sf *cpuhw, const struct hw_perf_event *hw
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if (n_sdb < CPUM_SF_MIN_SDB)
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n_sdb = CPUM_SF_MIN_SDB;
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/* Return if there is already a sampling buffer allocated.
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* XXX Remove this later and check number of available and
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* required sdb's and, if necessary, increase the sampling buffer.
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/* If there is already a sampling buffer allocated, it is very likely
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* that the sampling facility is enabled too. If the event to be
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* initialized requires a greater sampling buffer, the allocation must
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* be postponed. Changing the sampling buffer requires the sampling
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* facility to be in the disabled state. So, account the number of
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* required SDBs and let cpumsf_pmu_enable() resize the buffer just
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* before the event is started.
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*/
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sfb_init_allocs(n_sdb, hwc);
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if (sf_buffer_available(cpuhw))
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return 0;
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debug_sprintf_event(sfdbg, 3,
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"allocate_sdbt: rate=%lu f=%lu sdb=%lu/%i cpuhw=%p\n",
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"allocate_sdbt: rate=%lu f=%lu sdb=%lu/%lu cpuhw=%p\n",
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SAMPL_RATE(hwc), freq, n_sdb, CPUM_SF_MAX_SDB, cpuhw);
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return alloc_sampling_buffer(&cpuhw->sfb,
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min_t(unsigned long, n_sdb, CPUM_SF_MAX_SDB));
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sfb_pending_allocs(&cpuhw->sfb, hwc));
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}
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static unsigned long min_percent(unsigned int percent, unsigned long base,
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unsigned long min)
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{
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return min_t(unsigned long, min, DIV_ROUND_UP(percent * base, 100));
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}
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static unsigned long compute_sfb_extent(unsigned long ratio, unsigned long base)
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{
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/* Use a percentage-based approach to extend the sampling facility
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* buffer. Accept up to 5% sample data loss.
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* Vary the extents between 1% to 5% of the current number of
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* sample-data-blocks.
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*/
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if (ratio <= 5)
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return 0;
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if (ratio <= 25)
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||||
return min_percent(1, base, 1);
|
||||
if (ratio <= 50)
|
||||
return min_percent(1, base, 1);
|
||||
if (ratio <= 75)
|
||||
return min_percent(2, base, 2);
|
||||
if (ratio <= 100)
|
||||
return min_percent(3, base, 3);
|
||||
if (ratio <= 250)
|
||||
return min_percent(4, base, 4);
|
||||
|
||||
return min_percent(5, base, 8);
|
||||
}
|
||||
|
||||
static void sfb_account_overflows(struct cpu_hw_sf *cpuhw,
|
||||
struct hw_perf_event *hwc)
|
||||
{
|
||||
unsigned long ratio, num;
|
||||
|
||||
if (!OVERFLOW_REG(hwc))
|
||||
return;
|
||||
|
||||
/* The sample_overflow contains the average number of sample data
|
||||
* that has been lost because sample-data-blocks were full.
|
||||
*
|
||||
* Calculate the total number of sample data entries that has been
|
||||
* discarded. Then calculate the ratio of lost samples to total samples
|
||||
* per second in percent.
|
||||
*/
|
||||
ratio = DIV_ROUND_UP(100 * OVERFLOW_REG(hwc) * cpuhw->sfb.num_sdb,
|
||||
sample_rate_to_freq(&cpuhw->qsi, SAMPL_RATE(hwc)));
|
||||
|
||||
/* Compute number of sample-data-blocks */
|
||||
num = compute_sfb_extent(ratio, cpuhw->sfb.num_sdb);
|
||||
if (num)
|
||||
sfb_account_allocs(num, hwc);
|
||||
|
||||
debug_sprintf_event(sfdbg, 5, "sfb: overflow: overflow=%llu ratio=%lu"
|
||||
" num=%lu\n", OVERFLOW_REG(hwc), ratio, num);
|
||||
OVERFLOW_REG(hwc) = 0;
|
||||
}
|
||||
|
||||
/* extend_sampling_buffer() - Extend sampling buffer
|
||||
* @sfb: Sampling buffer structure (for local CPU)
|
||||
* @hwc: Perf event hardware structure
|
||||
*
|
||||
* Use this function to extend the sampling buffer based on the overflow counter
|
||||
* and postponed allocation extents stored in the specified Perf event hardware.
|
||||
*
|
||||
* Important: This function disables the sampling facility in order to safely
|
||||
* change the sampling buffer structure. Do not call this function
|
||||
* when the PMU is active.
|
||||
*/
|
||||
static void extend_sampling_buffer(struct sf_buffer *sfb,
|
||||
struct hw_perf_event *hwc)
|
||||
{
|
||||
unsigned long num, num_old;
|
||||
int rc;
|
||||
|
||||
num = sfb_pending_allocs(sfb, hwc);
|
||||
if (!num)
|
||||
return;
|
||||
num_old = sfb->num_sdb;
|
||||
|
||||
/* Disable the sampling facility to reset any states and also
|
||||
* clear pending measurement alerts.
|
||||
*/
|
||||
sf_disable();
|
||||
|
||||
/* Extend the sampling buffer.
|
||||
* This memory allocation typically happens in an atomic context when
|
||||
* called by perf. Because this is a reallocation, it is fine if the
|
||||
* new SDB-request cannot be satisfied immediately.
|
||||
*/
|
||||
rc = realloc_sampling_buffer(sfb, num, GFP_ATOMIC);
|
||||
if (rc)
|
||||
debug_sprintf_event(sfdbg, 5, "sfb: extend: realloc "
|
||||
"failed with rc=%i\n", rc);
|
||||
|
||||
if (sfb_has_pending_allocs(sfb, hwc))
|
||||
debug_sprintf_event(sfdbg, 5, "sfb: extend: "
|
||||
"req=%lu alloc=%lu remaining=%lu\n",
|
||||
num, sfb->num_sdb - num_old,
|
||||
sfb_pending_allocs(sfb, hwc));
|
||||
}
|
||||
|
||||
|
||||
@ -246,18 +480,6 @@ static atomic_t num_events;
|
||||
/* Used to avoid races in calling reserve/release_cpumf_hardware */
|
||||
static DEFINE_MUTEX(pmc_reserve_mutex);
|
||||
|
||||
/*
|
||||
* sf_disable() - Switch off sampling facility
|
||||
*/
|
||||
static int sf_disable(void)
|
||||
{
|
||||
struct hws_lsctl_request_block sreq;
|
||||
|
||||
memset(&sreq, 0, sizeof(sreq));
|
||||
return lsctl(&sreq);
|
||||
}
|
||||
|
||||
|
||||
#define PMC_INIT 0
|
||||
#define PMC_RELEASE 1
|
||||
#define PMC_FAILURE 2
|
||||
@ -345,19 +567,17 @@ static void hw_init_period(struct hw_perf_event *hwc, u64 period)
|
||||
}
|
||||
|
||||
static void hw_reset_registers(struct hw_perf_event *hwc,
|
||||
unsigned long sdbt_origin)
|
||||
unsigned long *sdbt_origin)
|
||||
{
|
||||
TEAR_REG(hwc) = sdbt_origin; /* (re)set to first sdb table */
|
||||
/* (Re)set to first sample-data-block-table */
|
||||
TEAR_REG(hwc) = (unsigned long) sdbt_origin;
|
||||
}
|
||||
|
||||
static unsigned long hw_limit_rate(const struct hws_qsi_info_block *si,
|
||||
unsigned long rate)
|
||||
{
|
||||
if (rate < si->min_sampl_rate)
|
||||
return si->min_sampl_rate;
|
||||
if (rate > si->max_sampl_rate)
|
||||
return si->max_sampl_rate;
|
||||
return rate;
|
||||
return clamp_t(unsigned long, rate,
|
||||
si->min_sampl_rate, si->max_sampl_rate);
|
||||
}
|
||||
|
||||
static int __hw_perf_event_init(struct perf_event *event)
|
||||
@ -448,6 +668,10 @@ static int __hw_perf_event_init(struct perf_event *event)
|
||||
SAMPL_RATE(hwc) = rate;
|
||||
hw_init_period(hwc, SAMPL_RATE(hwc));
|
||||
|
||||
/* Initialize sample data overflow accounting */
|
||||
hwc->extra_reg.reg = REG_OVERFLOW;
|
||||
OVERFLOW_REG(hwc) = 0;
|
||||
|
||||
/* Allocate the per-CPU sampling buffer using the CPU information
|
||||
* from the event. If the event is not pinned to a particular
|
||||
* CPU (event->cpu == -1; or cpuhw == NULL), allocate sampling
|
||||
@ -513,6 +737,7 @@ static int cpumsf_pmu_event_init(struct perf_event *event)
|
||||
static void cpumsf_pmu_enable(struct pmu *pmu)
|
||||
{
|
||||
struct cpu_hw_sf *cpuhw = &__get_cpu_var(cpu_hw_sf);
|
||||
struct hw_perf_event *hwc;
|
||||
int err;
|
||||
|
||||
if (cpuhw->flags & PMU_F_ENABLED)
|
||||
@ -521,6 +746,26 @@ static void cpumsf_pmu_enable(struct pmu *pmu)
|
||||
if (cpuhw->flags & PMU_F_ERR_MASK)
|
||||
return;
|
||||
|
||||
/* Check whether to extent the sampling buffer.
|
||||
*
|
||||
* Two conditions trigger an increase of the sampling buffer for a
|
||||
* perf event:
|
||||
* 1. Postponed buffer allocations from the event initialization.
|
||||
* 2. Sampling overflows that contribute to pending allocations.
|
||||
*
|
||||
* Note that the extend_sampling_buffer() function disables the sampling
|
||||
* facility, but it can be fully re-enabled using sampling controls that
|
||||
* have been saved in cpumsf_pmu_disable().
|
||||
*/
|
||||
if (cpuhw->event) {
|
||||
hwc = &cpuhw->event->hw;
|
||||
/* Account number of overflow-designated buffer extents */
|
||||
sfb_account_overflows(cpuhw, hwc);
|
||||
if (sfb_has_pending_allocs(&cpuhw->sfb, hwc))
|
||||
extend_sampling_buffer(&cpuhw->sfb, hwc);
|
||||
}
|
||||
|
||||
/* (Re)enable the PMU and sampling facility */
|
||||
cpuhw->flags |= PMU_F_ENABLED;
|
||||
barrier();
|
||||
|
||||
@ -632,8 +877,6 @@ static int perf_push_sample(struct perf_event *event,
|
||||
if (perf_event_overflow(event, &data, ®s)) {
|
||||
overflow = 1;
|
||||
event->pmu->stop(event, 0);
|
||||
debug_sprintf_event(sfdbg, 4, "perf_push_sample: PMU stopped"
|
||||
" because of an event overflow\n");
|
||||
}
|
||||
perf_event_update_userpage(event);
|
||||
|
||||
@ -710,11 +953,11 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all)
|
||||
struct hw_perf_event *hwc = &event->hw;
|
||||
struct hws_trailer_entry *te;
|
||||
unsigned long *sdbt;
|
||||
unsigned long long event_overflow, sampl_overflow;
|
||||
unsigned long long event_overflow, sampl_overflow, num_sdb;
|
||||
int done;
|
||||
|
||||
sdbt = (unsigned long *) TEAR_REG(hwc);
|
||||
done = event_overflow = sampl_overflow = 0;
|
||||
done = event_overflow = sampl_overflow = num_sdb = 0;
|
||||
while (!done) {
|
||||
/* Get the trailer entry of the sample-data-block */
|
||||
te = (struct hws_trailer_entry *) trailer_entry_ptr(*sdbt);
|
||||
@ -726,17 +969,13 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all)
|
||||
break;
|
||||
}
|
||||
|
||||
/* Check sample overflow count */
|
||||
if (te->overflow) {
|
||||
/* Increment sample overflow counter */
|
||||
sampl_overflow += te->overflow;
|
||||
|
||||
/* XXX: If an sample overflow occurs, increase the
|
||||
* sampling buffer. Set a "realloc" flag because
|
||||
* the sampler must be re-enabled for changing
|
||||
* the sample-data-block-table content.
|
||||
/* Check the sample overflow count */
|
||||
if (te->overflow)
|
||||
/* Account sample overflows and, if a particular limit
|
||||
* is reached, extend the sampling buffer.
|
||||
* For details, see sfb_account_overflows().
|
||||
*/
|
||||
}
|
||||
sampl_overflow += te->overflow;
|
||||
|
||||
/* Timestamps are valid for full sample-data-blocks only */
|
||||
debug_sprintf_event(sfdbg, 6, "hw_perf_event_update: sdbt=%p "
|
||||
@ -749,6 +988,7 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all)
|
||||
* is stopped and remaining samples will be discarded.
|
||||
*/
|
||||
hw_collect_samples(event, sdbt, &event_overflow);
|
||||
num_sdb++;
|
||||
|
||||
/* Reset trailer */
|
||||
xchg(&te->overflow, 0);
|
||||
@ -775,6 +1015,10 @@ static void hw_perf_event_update(struct perf_event *event, int flush_all)
|
||||
flush_all = 1;
|
||||
}
|
||||
|
||||
/* Account sample overflows in the event hardware structure */
|
||||
if (sampl_overflow)
|
||||
OVERFLOW_REG(hwc) = DIV_ROUND_UP(OVERFLOW_REG(hwc) +
|
||||
sampl_overflow, 1 + num_sdb);
|
||||
if (sampl_overflow || event_overflow)
|
||||
debug_sprintf_event(sfdbg, 4, "hw_perf_event_update: "
|
||||
"overflow stats: sample=%llu event=%llu\n",
|
||||
@ -849,7 +1093,7 @@ static int cpumsf_pmu_add(struct perf_event *event, int flags)
|
||||
*/
|
||||
cpuhw->lsctl.s = 0;
|
||||
cpuhw->lsctl.h = 1;
|
||||
cpuhw->lsctl.tear = cpuhw->sfb.sdbt;
|
||||
cpuhw->lsctl.tear = (unsigned long) cpuhw->sfb.sdbt;
|
||||
cpuhw->lsctl.dear = *(unsigned long *) cpuhw->sfb.sdbt;
|
||||
cpuhw->lsctl.interval = SAMPL_RATE(&event->hw);
|
||||
hw_reset_registers(&event->hw, cpuhw->sfb.sdbt);
|
||||
@ -1018,6 +1262,48 @@ static int __cpuinit cpumf_pmu_notifier(struct notifier_block *self,
|
||||
return NOTIFY_OK;
|
||||
}
|
||||
|
||||
static int param_get_sfb_size(char *buffer, const struct kernel_param *kp)
|
||||
{
|
||||
if (!cpum_sf_avail())
|
||||
return -ENODEV;
|
||||
return sprintf(buffer, "%lu,%lu", CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB);
|
||||
}
|
||||
|
||||
static int param_set_sfb_size(const char *val, const struct kernel_param *kp)
|
||||
{
|
||||
int rc;
|
||||
unsigned long min, max;
|
||||
|
||||
if (!cpum_sf_avail())
|
||||
return -ENODEV;
|
||||
if (!val || !strlen(val))
|
||||
return -EINVAL;
|
||||
|
||||
/* Valid parameter values: "min,max" or "max" */
|
||||
min = CPUM_SF_MIN_SDB;
|
||||
max = CPUM_SF_MAX_SDB;
|
||||
if (strchr(val, ','))
|
||||
rc = (sscanf(val, "%lu,%lu", &min, &max) == 2) ? 0 : -EINVAL;
|
||||
else
|
||||
rc = kstrtoul(val, 10, &max);
|
||||
|
||||
if (min < 2 || min >= max || max > get_num_physpages())
|
||||
rc = -EINVAL;
|
||||
if (rc)
|
||||
return rc;
|
||||
|
||||
sfb_set_limits(min, max);
|
||||
pr_info("Changed sampling buffer settings: min=%lu max=%lu\n",
|
||||
CPUM_SF_MIN_SDB, CPUM_SF_MAX_SDB);
|
||||
return 0;
|
||||
}
|
||||
|
||||
#define param_check_sfb_size(name, p) __param_check(name, p, void)
|
||||
static struct kernel_param_ops param_ops_sfb_size = {
|
||||
.set = param_set_sfb_size,
|
||||
.get = param_get_sfb_size,
|
||||
};
|
||||
|
||||
static int __init init_cpum_sampling_pmu(void)
|
||||
{
|
||||
int err;
|
||||
@ -1047,3 +1333,4 @@ out:
|
||||
return err;
|
||||
}
|
||||
arch_initcall(init_cpum_sampling_pmu);
|
||||
core_param(cpum_sfb_size, CPUM_SF_MAX_SDB, sfb_size, 0640);
|
||||
|
||||
Loading…
Reference in New Issue
Block a user