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Message-ID: <d071bb27-5533-da2f-9f8f-808183e04794@huawei.com>
Date: Thu, 4 Oct 2018 10:20:39 +0100
From: John Garry <john.garry@...wei.com>
To: Jiri Olsa <jolsa@...hat.com>
CC: Andi Kleen <ak@...ux.intel.com>, Ingo Molnar <mingo@...hat.com>,
"Peter Zijlstra" <peterz@...radead.org>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Linuxarm <linuxarm@...wei.com>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
Namhyung Kim <namhyung@...nel.org>,
"Will Deacon" <will.deacon@....com>,
Mark Rutland <mark.rutland@....com>
Subject: Re: [PATCH] perf tools: Store ids for events with their own cpus
perf_event__synthesize_event_update_cpus
>>> Hi Jirka,
>>>
>>> Can you please double-check your new patch, as I'm getting this now:
>>> root@...alhost:~# ./perf_debug record -e armv8_pmuv3_0/br_mis_pred/ sleep 1
>>> [ perf record: Woken up 1 times to write data ]
>>> [ perf record: Captured and wrote 0.001 MB perf.data (6 samples) ]
>>> root@...alhost:~# ./perf_debug report
>>> 0xe8 [0]: failed to process type: 461
>>> Error:
>>> failed to process sample
>>> # To display the perf.data header info, please use --header/--header-only
>>> option
>>> #
>>> root@...alhost:~#
>>
>> ok, I need to get a machine to test this.. but it looks like
>> any sample-able events with cpumask are in arm :-\ will try
>> to get some..
>
> got an arm server and patch below works for me.. could you please test?
>
Cool, so this works ok:
root@...alhost:~# ./perf_debug record -e armv8_pmuv3_0/br_mis_pred/ sleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.002 MB perf.data (6 samples) ]
root@...alhost:~# ./perf_debug report
# To display the perf.data header info, please use
--header/--header-only option
#
#
# Total Lost Samples: 0
#
# Samples: 6 of event 'armv8_pmuv3_0/br_mis_pred/'
# Event count (approx.): 3369
#
# Overhead Command Shared Object Symbol
# ........ ....... ................. ...................
#
94.81% sleep [kernel.kallsyms] [k] memcmp
4.87% sleep [kernel.kallsyms] [k] tlb_flush_mmu
0.33% perf_de [kernel.kallsyms] [k] perf_event_exec
#
# (Cannot load tips.txt file, please install perf!)
#
root@...alhost:~#
> thanks,
> jirka
>
>
> ---
>
> John reported crash when recording on an event under
> pmu with cpumask defined:
>
> root@...alhost:~# ./perf_debug_ record -e armv8_pmuv3_0/br_mis_pred/ sleep 1
> perf: Segmentation fault
> Obtained 9 stack frames.
> ./perf_debug_() [0x4c5ef8]
> [0xffff82ba267c]
> ./perf_debug_() [0x4bc5a8]
> ./perf_debug_() [0x419550]
> ./perf_debug_() [0x41a928]
> ./perf_debug_() [0x472f58]
> ./perf_debug_() [0x473210]
> ./perf_debug_() [0x4070f4]
> /lib/aarch64-linux-gnu/libc.so.6(__libc_start_main+0xe0) [0xffff8294c8a0]
> Segmentation fault (core dumped)
>
> We synthesize an update event that needs to touch the evsel
> id array, which is not defined at that time. Fixing this by
> forcing the id allocation for events with theeir own cpus.
>
> Reported-by: John Garry <john.garry@...wei.com>
> Link: http://lkml.kernel.org/n/tip-8x4n7o34yheigoxm1jibflm6@git.kernel.org
Tested-by: John Garry <john.garry@...wei.com>
In terms of adding to stable, LT v4.14 is not affected, but 4.18.x is.
Thanks,
John
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
> tools/perf/builtin-report.c | 1 +
> tools/perf/util/evsel.c | 3 +++
> 2 files changed, 4 insertions(+)
>
> diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
> index c0703979c51d..257c9c18cb7e 100644
> --- a/tools/perf/builtin-report.c
> +++ b/tools/perf/builtin-report.c
> @@ -980,6 +980,7 @@ int cmd_report(int argc, const char **argv)
> .id_index = perf_event__process_id_index,
> .auxtrace_info = perf_event__process_auxtrace_info,
> .auxtrace = perf_event__process_auxtrace,
> + .event_update = perf_event__process_event_update,
> .feature = process_feature_event,
> .ordered_events = true,
> .ordering_requires_timestamps = true,
> diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c
> index ac6cfb8b085e..7a0d5fbaf3c1 100644
> --- a/tools/perf/util/evsel.c
> +++ b/tools/perf/util/evsel.c
> @@ -1088,6 +1088,9 @@ void perf_evsel__config(struct perf_evsel *evsel, struct record_opts *opts,
> attr->exclude_user = 1;
> }
>
> + if (evsel->own_cpus)
> + evsel->attr.read_format |= PERF_FORMAT_ID;
> +
> /*
> * Apply event specific term settings,
> * it overloads any global configuration.
>
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