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Message-ID: <8c47cb2a-2bea-422d-b16c-f304ab4ff470@linaro.org>
Date: Wed, 4 Sep 2024 14:28:26 +0100
From: James Clark <james.clark@...aro.org>
To: Namhyung Kim <namhyung@...nel.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>
Cc: Jiri Olsa <jolsa@...nel.org>, Adrian Hunter <adrian.hunter@...el.com>,
Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...nel.org>,
LKML <linux-kernel@...r.kernel.org>, linux-perf-users@...r.kernel.org,
Ravi Bangoria <ravi.bangoria@....com>, Mark Rutland <mark.rutland@....com>,
James Clark <james.clark@....com>,
Athira Rajeev <atrajeev@...ux.vnet.ibm.com>, Kajol Jain
<kjain@...ux.ibm.com>, Thomas Richter <tmricht@...ux.ibm.com>,
Atish Patra <atishp@...shpatra.org>, Palmer Dabbelt <palmer@...osinc.com>,
Mingwei Zhang <mizhang@...gle.com>, Ian Rogers <irogers@...gle.com>,
Kan Liang <kan.liang@...ux.intel.com>
Subject: Re: [PATCH 7/8] perf tools: Add fallback for exclude_guest
On 04/09/2024 7:41 am, Namhyung Kim wrote:
> It seems Apple M1 PMU requires exclude_guest set and returns EOPNOTSUPP
> if not. Let's add a fallback so that it can work with default events.
>
> Cc: Mark Rutland <mark.rutland@....com>
> Cc: James Clark <james.clark@...aro.org>
> Signed-off-by: Namhyung Kim <namhyung@...nel.org>
> ---
> tools/perf/util/evsel.c | 21 +++++++++++++++++++++
> 1 file changed, 21 insertions(+)
>
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index 0de0a72947db3f10..8c4d70f7b2f5b880 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -3400,6 +3400,27 @@ bool evsel__fallback(struct evsel *evsel, struct target *target, int err,
> "to fall back to excluding hypervisor samples", paranoid);
> evsel->core.attr.exclude_hv = 1;
>
> + return true;
> + } else if (err == EOPNOTSUPP && !evsel->core.attr.exclude_guest &&
> + !evsel->exclude_GH) {
> + const char *name = evsel__name(evsel);
> + char *new_name;
> + const char *sep = ":";
> +
> + /* Is there already the separator in the name. */
> + if (strchr(name, '/') ||
> + (strchr(name, ':') && !evsel->is_libpfm_event))
> + sep = "";
> +
> + if (asprintf(&new_name, "%s%su", name, sep) < 0)
> + return false;
> +
> + free(evsel->name);
> + evsel->name = new_name;
> + /* Apple M1 requires exclude_guest */
> + scnprintf(msg, msgsize, "trying to fall back to excluding guest samples");
> + evsel->core.attr.exclude_guest = 1;
> +
> return true;
> }
>
Not sure if this is working, for some reason it doesn't try the
fallback. With exclude guest made mandatory in the Arm PMU, then:
$ perf stat -e cycles -vvv -- true
Control descriptor is not initialized
Opening: cycles
------------------------------------------------------------
perf_event_attr:
type 0 (PERF_TYPE_HARDWARE)
size 136
config 0xb00000000
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
disabled 1
inherit 1
enable_on_exec 1
------------------------------------------------------------
sys_perf_event_open: pid 698 cpu -1 group_fd -1 flags 0x8
sys_perf_event_open failed, error -95
Warning:
cycles event is not supported by the kernel.
Opening: cycles
------------------------------------------------------------
perf_event_attr:
type 0 (PERF_TYPE_HARDWARE)
size 136
config 0xa00000000
sample_type IDENTIFIER
read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING
disabled 1
inherit 1
enable_on_exec 1
------------------------------------------------------------
sys_perf_event_open: pid 698 cpu -1 group_fd -1 flags 0x8
sys_perf_event_open failed, error -95
Warning:
cycles event is not supported by the kernel.
failed to read counter cycles
failed to read counter cycles
Performance counter stats for 'true':
<not supported> armv8_cortex_a53/cycles/
<not supported> armv8_cortex_a57/cycles/
Other than that, all the tests are passing on Juno (without the
exclude_guest requirement).
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