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perf intel-pt: Add support for recording AUX area samples

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Set up the default number of mmap pages, default sample size and default
psb_period for AUX area sampling. Add documentation also.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lore.kernel.org/lkml/20191115124225.5247-14-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter
2019-11-15 14:42:23 +02:00
committed by Arnaldo Carvalho de Melo
parent a1ac7de690
commit c4ab2f0f76
3 changed files with 139 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
tools/perf/arch/x86/util/auxtrace.c
View File

@@ -26,6 +26,8 @@ struct auxtrace_record *auxtrace_record__init_intel(struct evlist *evlist,
bool found_bts = false;
intel_pt_pmu = perf_pmu__find(INTEL_PT_PMU_NAME);
if (intel_pt_pmu)
intel_pt_pmu->auxtrace = true;
intel_bts_pmu = perf_pmu__find(INTEL_BTS_PMU_NAME);
evlist__for_each_entry(evlist, evsel) {

81
tools/perf/arch/x86/util/intel-pt.c
View File

@@ -17,6 +17,7 @@
#include "../../util/event.h"
#include "../../util/evlist.h"
#include "../../util/evsel.h"
#include "../../util/evsel_config.h"
#include "../../util/cpumap.h"
#include "../../util/mmap.h"
#include <subcmd/parse-options.h>
@@ -551,6 +552,43 @@ static int intel_pt_validate_config(struct perf_pmu *intel_pt_pmu,
evsel->core.attr.config);
}
static void intel_pt_config_sample_mode(struct perf_pmu *intel_pt_pmu,
struct evsel *evsel)
{
struct perf_evsel_config_term *term;
u64 user_bits = 0, bits;
term = perf_evsel__get_config_term(evsel, CFG_CHG);
if (term)
user_bits = term->val.cfg_chg;
bits = perf_pmu__format_bits(&intel_pt_pmu->format, "psb_period");
/* Did user change psb_period */
if (bits & user_bits)
return;
/* Set psb_period to 0 */
evsel->core.attr.config &= ~bits;
}
static void intel_pt_min_max_sample_sz(struct evlist *evlist,
size_t *min_sz, size_t *max_sz)
{
struct evsel *evsel;
evlist__for_each_entry(evlist, evsel) {
size_t sz = evsel->core.attr.aux_sample_size;
if (!sz)
continue;
if (min_sz && (sz < *min_sz || !*min_sz))
*min_sz = sz;
if (max_sz && sz > *max_sz)
*max_sz = sz;
}
}
/*
* Currently, there is not enough information to disambiguate different PEBS
* events, so only allow one.
@@ -606,6 +644,11 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
return -EINVAL;
}
if (opts->auxtrace_snapshot_mode && opts->auxtrace_sample_mode) {
pr_err("Snapshot mode (" INTEL_PT_PMU_NAME " PMU) and sample trace cannot be used together\n");
return -EINVAL;
}
if (opts->use_clockid) {
pr_err("Cannot use clockid (-k option) with " INTEL_PT_PMU_NAME "\n");
return -EINVAL;
@@ -617,6 +660,9 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
if (!opts->full_auxtrace)
return 0;
if (opts->auxtrace_sample_mode)
intel_pt_config_sample_mode(intel_pt_pmu, intel_pt_evsel);
err = intel_pt_validate_config(intel_pt_pmu, intel_pt_evsel);
if (err)
return err;
@@ -666,6 +712,34 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
opts->auxtrace_snapshot_size, psb_period);
}
/* Set default sizes for sample mode */
if (opts->auxtrace_sample_mode) {
size_t psb_period = intel_pt_psb_period(intel_pt_pmu, evlist);
size_t min_sz = 0, max_sz = 0;
intel_pt_min_max_sample_sz(evlist, &min_sz, &max_sz);
if (!opts->auxtrace_mmap_pages && !privileged &&
opts->mmap_pages == UINT_MAX)
opts->mmap_pages = KiB(256) / page_size;
if (!opts->auxtrace_mmap_pages) {
size_t sz = round_up(max_sz, page_size) / page_size;
opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
}
if (max_sz > opts->auxtrace_mmap_pages * (size_t)page_size) {
pr_err("Sample size %zu must not be greater than AUX area tracing mmap size %zu\n",
max_sz,
opts->auxtrace_mmap_pages * (size_t)page_size);
return -EINVAL;
}
pr_debug2("Intel PT min. sample size: %zu max. sample size: %zu\n",
min_sz, max_sz);
if (psb_period &&
min_sz <= psb_period + INTEL_PT_PSB_PERIOD_NEAR)
ui__warning("Intel PT sample size (%zu) may be too small for PSB period (%zu)\n",
min_sz, psb_period);
}
/* Set default sizes for full trace mode */
if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
if (privileged) {
@@ -682,7 +756,7 @@ static int intel_pt_recording_options(struct auxtrace_record *itr,
size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
size_t min_sz;
if (opts->auxtrace_snapshot_mode)
if (opts->auxtrace_snapshot_mode || opts->auxtrace_sample_mode)
min_sz = KiB(4);
else
min_sz = KiB(8);
@@ -1136,5 +1210,10 @@ struct auxtrace_record *intel_pt_recording_init(int *err)
ptr->itr.parse_snapshot_options = intel_pt_parse_snapshot_options;
ptr->itr.reference = intel_pt_reference;
ptr->itr.read_finish = intel_pt_read_finish;
/*
* Decoding starts at a PSB packet. Minimum PSB period is 2K so 4K
* should give at least 1 PSB per sample.
*/
ptr->itr.default_aux_sample_size = 4096;
return &ptr->itr;
}