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x86: Improve Intel microcode loader performance

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We've noticed that on large SGI UV system configurations,
running microcode.ctl can take very long periods of time.  This
is due to the large number of vmalloc/vfree calls made by the
Intel generic_load_microcode() logic.

By reusing allocated space, the following patch reduces the time
to run microcode.ctl on a 1024 cpu system from approximately 80
seconds down to 1 or 2 seconds.

Signed-off-by: Dimitri Sivanich <sivanich@sgi.com>
Acked-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Cc: Avi Kivity <avi@redhat.com>
Cc: Bill Davidsen <davidsen@tmr.com>
LKML-Reference: <20100305174203.GA19638@sgi.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Dimitri Sivanich 2010-03-05 11:42:03 -06:00 committed by Ingo Molnar
parent 522dba7134
commit 938179b4f8
1 changed files with 16 additions and 6 deletions
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16
arch/x86/kernel/microcode_intel.c
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@ -343,10 +343,11 @@ static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
int (*get_ucode_data)(void *, const void *, size_t))
{
struct ucode_cpu_info *uci = ucode_cpu_info + cpu;
u8 *ucode_ptr = data, *new_mc = NULL, *mc;
u8 *ucode_ptr = data, *new_mc = NULL, *mc = NULL;
int new_rev = uci->cpu_sig.rev;
unsigned int leftover = size;
enum ucode_state state = UCODE_OK;
unsigned int curr_mc_size = 0;
while (leftover) {
struct microcode_header_intel mc_header;
@ -361,9 +362,15 @@ static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
break;
}
/* For performance reasons, reuse mc area when possible */
if (!mc || mc_size > curr_mc_size) {
if (mc)
vfree(mc);
mc = vmalloc(mc_size);
if (!mc)
break;
curr_mc_size = mc_size;
}
if (get_ucode_data(mc, ucode_ptr, mc_size) ||
microcode_sanity_check(mc) < 0) {
@ -376,13 +383,16 @@ static enum ucode_state generic_load_microcode(int cpu, void *data, size_t size,
vfree(new_mc);
new_rev = mc_header.rev;
new_mc = mc;
} else
vfree(mc);
mc = NULL; /* trigger new vmalloc */
}
ucode_ptr += mc_size;
leftover -= mc_size;
}
if (mc)
vfree(mc);
if (leftover) {
if (new_mc)
vfree(new_mc);