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e293a5e816
The PMU information is in the kernel sysfs so it needs to scan the directory to get the whole information like event aliases, formats and so on. During the traversal, it opens a lot of files and directories like below: dir = opendir("/sys/bus/event_source/devices"); while (dentry = readdir(dir)) { char buf[PATH_MAX]; snprintf(buf, sizeof(buf), "%s/%s", "/sys/bus/event_source/devices", dentry->d_name); fd = open(buf, O_RDONLY); ... } But this is not good since it needs to copy the string to build the absolute pathname, and it makes redundant pathname walk (from the /sys) unnecessarily. We can use openat(2) to open the file in the given directory. While it's not a problem ususally, it can be a problem when the kernel has contentions on the sysfs. Add a couple of new helper to return the file descriptor of PMU directory so that it can use it with relative paths. * perf_pmu__event_source_devices_fd() - returns a fd for the PMU root ("/sys/bus/event_source/devices") * perf_pmu__pathname_fd() - returns a fd for "<pmu>/<file>" under the PMU root Now the above code can be converted something like below: dirfd = perf_pmu__event_source_devices_fd(); dir = fdopendir(dirfd); while (dentry = readdir(dir)) { fd = openat(dirfd, dentry->d_name, O_RDONLY); ... } Signed-off-by: Namhyung Kim <namhyung@kernel.org> Acked-by: Ian Rogers <irogers@google.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Leo Yan <leo.yan@linaro.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: https://lore.kernel.org/r/20230331202949.810326-2-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
189 lines
4.1 KiB
C
189 lines
4.1 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include "parse-events.h"
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#include "pmu.h"
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#include "tests.h"
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#include <errno.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <linux/kernel.h>
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#include <linux/limits.h>
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/* Simulated format definitions. */
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static struct test_format {
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const char *name;
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const char *value;
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} test_formats[] = {
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{ "krava01", "config:0-1,62-63\n", },
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{ "krava02", "config:10-17\n", },
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{ "krava03", "config:5\n", },
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{ "krava11", "config1:0,2,4,6,8,20-28\n", },
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{ "krava12", "config1:63\n", },
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{ "krava13", "config1:45-47\n", },
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{ "krava21", "config2:0-3,10-13,20-23,30-33,40-43,50-53,60-63\n", },
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{ "krava22", "config2:8,18,48,58\n", },
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{ "krava23", "config2:28-29,38\n", },
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};
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/* Simulated users input. */
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static struct parse_events_term test_terms[] = {
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{
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.config = (char *) "krava01",
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.val.num = 15,
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.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
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.type_term = PARSE_EVENTS__TERM_TYPE_USER,
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},
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{
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.config = (char *) "krava02",
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.val.num = 170,
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.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
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.type_term = PARSE_EVENTS__TERM_TYPE_USER,
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},
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{
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.config = (char *) "krava03",
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.val.num = 1,
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.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
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.type_term = PARSE_EVENTS__TERM_TYPE_USER,
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},
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{
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.config = (char *) "krava11",
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.val.num = 27,
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.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
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.type_term = PARSE_EVENTS__TERM_TYPE_USER,
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},
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{
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.config = (char *) "krava12",
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.val.num = 1,
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.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
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.type_term = PARSE_EVENTS__TERM_TYPE_USER,
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},
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{
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.config = (char *) "krava13",
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.val.num = 2,
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.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
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.type_term = PARSE_EVENTS__TERM_TYPE_USER,
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},
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{
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.config = (char *) "krava21",
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.val.num = 119,
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.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
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.type_term = PARSE_EVENTS__TERM_TYPE_USER,
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},
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{
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.config = (char *) "krava22",
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.val.num = 11,
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.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
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.type_term = PARSE_EVENTS__TERM_TYPE_USER,
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},
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{
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.config = (char *) "krava23",
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.val.num = 2,
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.type_val = PARSE_EVENTS__TERM_TYPE_NUM,
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.type_term = PARSE_EVENTS__TERM_TYPE_USER,
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},
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};
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/*
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* Prepare format directory data, exported by kernel
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* at /sys/bus/event_source/devices/<dev>/format.
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*/
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static char *test_format_dir_get(void)
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{
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static char dir[PATH_MAX];
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unsigned int i;
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snprintf(dir, PATH_MAX, "/tmp/perf-pmu-test-format-XXXXXX");
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if (!mkdtemp(dir))
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return NULL;
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for (i = 0; i < ARRAY_SIZE(test_formats); i++) {
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static char name[PATH_MAX];
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struct test_format *format = &test_formats[i];
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FILE *file;
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scnprintf(name, PATH_MAX, "%s/%s", dir, format->name);
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file = fopen(name, "w");
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if (!file)
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return NULL;
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if (1 != fwrite(format->value, strlen(format->value), 1, file))
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break;
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fclose(file);
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}
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return dir;
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}
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/* Cleanup format directory. */
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static int test_format_dir_put(char *dir)
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{
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char buf[PATH_MAX];
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snprintf(buf, PATH_MAX, "rm -f %s/*\n", dir);
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if (system(buf))
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return -1;
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snprintf(buf, PATH_MAX, "rmdir %s\n", dir);
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return system(buf);
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}
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static struct list_head *test_terms_list(void)
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{
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static LIST_HEAD(terms);
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unsigned int i;
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for (i = 0; i < ARRAY_SIZE(test_terms); i++)
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list_add_tail(&test_terms[i].list, &terms);
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return &terms;
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}
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static int test__pmu(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
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{
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char *format = test_format_dir_get();
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LIST_HEAD(formats);
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struct list_head *terms = test_terms_list();
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int ret;
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if (!format)
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return -EINVAL;
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do {
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struct perf_event_attr attr;
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int fd;
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memset(&attr, 0, sizeof(attr));
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fd = open(format, O_DIRECTORY);
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if (fd < 0) {
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ret = fd;
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break;
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}
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ret = perf_pmu__format_parse(fd, &formats);
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if (ret)
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break;
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ret = perf_pmu__config_terms("perf-pmu-test", &formats, &attr,
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terms, false, NULL);
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if (ret)
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break;
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ret = -EINVAL;
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if (attr.config != 0xc00000000002a823)
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break;
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if (attr.config1 != 0x8000400000000145)
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break;
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if (attr.config2 != 0x0400000020041d07)
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break;
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ret = 0;
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} while (0);
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perf_pmu__del_formats(&formats);
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test_format_dir_put(format);
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return ret;
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}
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DEFINE_SUITE("Parse perf pmu format", pmu);
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