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Date: Wed, 22 Nov 2023 13:55:19 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Mark Rutland <mark.rutland@....com>, Marc Zyngier <maz@...nel.org>,
Hector Martin <marcan@...can.st>,
Arnaldo Carvalho de Melo <acme@...hat.com>,
James Clark <james.clark@....com>,
linux-perf-users@...r.kernel.org,
LKML <linux-kernel@...r.kernel.org>,
Asahi Linux <asahi@...ts.linux.dev>
Subject: Re: [REGRESSION] Perf (userspace) broken on big.LITTLE systems since
v6.5
Em Wed, Nov 22, 2023 at 08:29:58AM -0800, Ian Rogers escreveu:
> I can look at doing an event parser change like:
>
> ```
> diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
> index aa2f5c6fc7fc..9a18fda525d2 100644
> --- a/tools/perf/util/parse-events.c
> +++ b/tools/perf/util/parse-events.c
> @@ -986,7 +986,8 @@ static int config_term_pmu(struct perf_event_attr *attr,
> err_str,
> /*help=*/NULL);
> return -EINVAL;
> }
> - if (perf_pmu__supports_legacy_cache(pmu)) {
> + if (perf_pmu__supports_legacy_cache(pmu) &&
> + !perf_pmu__have_event(pmu, term->val.str)) {
> attr->type = PERF_TYPE_HW_CACHE;
> return
> parse_events__decode_legacy_cache(term->config, pmu->type,
> &attr->config);
> @@ -1004,10 +1005,15 @@ static int config_term_pmu(struct perf_event_attr *attr,
> err_str,
> /*help=*/NULL);
> return -EINVAL;
> }
> - attr->type = PERF_TYPE_HARDWARE;
> - attr->config = term->val.num;
> - if (perf_pmus__supports_extended_type())
> - attr->config |= (__u64)pmu->type << PERF_PMU_TYPE_SHIFT;
> + if (perf_pmu__have_event(pmu, term->val.str)) {
> + /* If the PMU has a sysfs or json event prefer
> it over legacy. ARM requires this. */
> + term->term_type = PARSE_EVENTS__TERM_TYPE_USER;
> + } else {
> + attr->type = PERF_TYPE_HARDWARE;
> + attr->config = term->val.num;
> + if (perf_pmus__supports_extended_type())
> + attr->config |= (__u64)pmu->type <<
> PERF_PMU_TYPE_SHIFT;
> + }
> return 0;
> }
> if (term->type_term == PARSE_EVENTS__TERM_TYPE_USER ||
> ```
> (note: this is incomplete as term->val.str isn't populated for
> PARSE_EVENTS__TERM_TYPE_HARDWARE)
Yeah, I had to apply manually as your MUA mangled it, then it didn't
build, had to remove some consts, then there was a struct member
mistake, after all fixed I get to the patch below, but it now segfaults,
probably what you mention...
root@...-rk3399-pc:~# strace -e perf_event_open taskset -c 4,5 perf stat -v -e cycles,armv8_cortex_a53/cycles/,armv8_cortex_a72/cycles/ echo
Using CPUID 0x00000000410fd082
perf_event_open({type=PERF_TYPE_HARDWARE, size=0 /* PERF_ATTR_SIZE_??? */, config=0x7<<32|PERF_COUNT_HW_CPU_CYCLES, sample_period=0, sample_type=0, read_format=0, disabled=1, precise_ip=0 /* arbitrary skid */, ...}, 0, -1, -1, PERF_FLAG_FD_CLOEXEC) = -1 ENOENT (No such file or directory)
--- SIGSEGV {si_signo=SIGSEGV, si_code=SEGV_MAPERR, si_addr=NULL} ---
+++ killed by SIGSEGV +++
Segmentation fault
root@...-rk3399-pc:~#
- Arnaldo
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index aa2f5c6fc7fc..1e648454cc49 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -976,7 +976,7 @@ static int config_term_pmu(struct perf_event_attr *attr,
struct parse_events_error *err)
{
if (term->type_term == PARSE_EVENTS__TERM_TYPE_LEGACY_CACHE) {
- const struct perf_pmu *pmu = perf_pmus__find_by_type(attr->type);
+ struct perf_pmu *pmu = perf_pmus__find_by_type(attr->type);
if (!pmu) {
char *err_str;
@@ -986,7 +986,8 @@ static int config_term_pmu(struct perf_event_attr *attr,
err_str, /*help=*/NULL);
return -EINVAL;
}
- if (perf_pmu__supports_legacy_cache(pmu)) {
+ if (perf_pmu__supports_legacy_cache(pmu) &&
+ !perf_pmu__have_event(pmu, term->val.str)) {
attr->type = PERF_TYPE_HW_CACHE;
return parse_events__decode_legacy_cache(term->config, pmu->type,
&attr->config);
@@ -994,7 +995,7 @@ static int config_term_pmu(struct perf_event_attr *attr,
term->type_term = PARSE_EVENTS__TERM_TYPE_USER;
}
if (term->type_term == PARSE_EVENTS__TERM_TYPE_HARDWARE) {
- const struct perf_pmu *pmu = perf_pmus__find_by_type(attr->type);
+ struct perf_pmu *pmu = perf_pmus__find_by_type(attr->type);
if (!pmu) {
char *err_str;
@@ -1004,10 +1005,15 @@ static int config_term_pmu(struct perf_event_attr *attr,
err_str, /*help=*/NULL);
return -EINVAL;
}
- attr->type = PERF_TYPE_HARDWARE;
- attr->config = term->val.num;
- if (perf_pmus__supports_extended_type())
- attr->config |= (__u64)pmu->type << PERF_PMU_TYPE_SHIFT;
+ if (perf_pmu__have_event(pmu, term->val.str)) {
+ /* If the PMU has a sysfs or JSON event prefer it over legacy. ARM requires this. */
+ term->type_term = PARSE_EVENTS__TERM_TYPE_USER;
+ } else {
+ attr->type = PERF_TYPE_HARDWARE;
+ attr->config = term->val.num;
+ if (perf_pmus__supports_extended_type())
+ attr->config |= (__u64)pmu->type << PERF_PMU_TYPE_SHIFT;
+ }
return 0;
}
if (term->type_term == PARSE_EVENTS__TERM_TYPE_USER ||
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