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Date: Fri, 8 Dec 2023 14:39:37 -0500
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
Ian Rogers <irogers@...gle.com>
Cc: Mark Rutland <mark.rutland@....com>, Marc Zyngier <maz@...nel.org>,
Hector Martin <marcan@...can.st>,
Namhyung Kim <namhyung@...nel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
linux-perf-users@...r.kernel.org
Subject: Re: 'perf top' broken on intel hybrid systems
On 2023-12-08 1:57 p.m., Arnaldo Carvalho de Melo wrote:
> Hi,
>
> So I finally got a recent Intel hybrid system:
>
> root@...ora:~# grep -m1 "model name" /proc/cpuinfo
> model name : Intel(R) Core(TM) i7-14700K
> root@...ora:~#
>
> Most things work, but:
>
> root@...ora:~# perf top
>
> Error:
> The cycles:P event is not supported.
> root@...ora:~#
>
> root@...ora:~# perf top -e cycles:p
> Error:
> The cycles:p event is not supported.
> root@...ora:~# perf top -e cycles:pp
> Error:
> The cycles:pp event is not supported.
> ^[[Aroot@...ora:~# perf top -e cycles:ppp
> Error:
> The cycles:ppp event is not supported.
> root@...ora:~#
> root@...ora:~# perf top -e cycles
> Error:
> The cycles event is not supported.
> root@...ora:~#
>
> root@...ora:~# perf top -e instructions
> Error:
> The instructions event is not supported.
> root@...ora:~#root@...ora:~# perf top -e cache-misses
> Error:
> The cache-misses event is not supported.
> root@...ora:~#
>
> ------------------------------------------------------------
> perf_event_attr:
> type 0 (PERF_TYPE_HARDWARE)
> size 136
> config 0xa00000000
> { sample_period, sample_freq } 4000
> sample_type IP|TID|TIME|ID|CPU|PERIOD
> read_format ID|LOST
> disabled 1
> inherit 1
> mmap 1
> comm 1
> freq 1
> task 1
> sample_id_all 1
> exclude_guest 1
> mmap2 1
> comm_exec 1
> ksymbol 1
> bpf_event 1
> ------------------------------------------------------------
> sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8
> sys_perf_event_open failed, error -2
The error is because the perf top always tries to open an event on the
user_requested_cpus, which are all CPUs by default.
Something as below should fix it. For hybrid, open a PMU event on an
unsupported CPU should be error out.
diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 1e42bd1c7d5a..7aa29e6264e4 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -1027,8 +1027,8 @@ static int perf_top__start_counters(struct
perf_top *top)
evlist__for_each_entry(evlist, counter) {
try_again:
- if (evsel__open(counter,
top->evlist->core.user_requested_cpus,
- top->evlist->core.threads) < 0) {
+ if (evsel__open(counter, counter->core.cpus,
+ counter->core.threads) < 0) {
/*
* Specially handle overwrite fall back.
> Error:
> The cycles event is not supported.
> root@...ora:~#
>
> But...
>
> root@...ora:~# perf record
> ^C[ perf record: Woken up 1 times to write data ]
> [ perf record: Captured and wrote 2.631 MB perf.data (24079 samples) ]
>
> root@...ora:~# perf evlist -v
> cpu_atom/cycles:P/: type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0xa00000000, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, inherit: 1, freq: 1, precise_ip: 3, sample_id_all: 1
> cpu_core/cycles:P/: type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0x400000000, { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CPU|PERIOD|IDENTIFIER, read_format: ID|LOST, disabled: 1, inherit: 1, freq: 1, precise_ip: 3, sample_id_all: 1
> dummy:u: type: 1 (PERF_TYPE_SOFTWARE), size: 136, config: 0x9 (PERF_COUNT_SW_DUMMY), { sample_period, sample_freq }: 1, sample_type: IP|TID|TIME|CPU|IDENTIFIER, read_format: ID|LOST, inherit: 1, exclude_kernel: 1, exclude_hv: 1, mmap: 1, comm: 1, task: 1, sample_id_all: 1, exclude_guest: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1
> root@...ora:~#
>
>
> root@...ora:~# perf top -e cpu_core/cpu-cycles:P/
> event syntax error: 'cpu_core/cpu-cycles:P/'
> \___ Bad event or PMU
>
> Unable to find PMU or event on a PMU of 'cpu_core'
>
> Initial error:
> event syntax error: 'cpu_core/cpu-cycles:P/'
> \___ unknown term 'cpu-cycles:P' for pmu 'cpu_core'
The P or other event modifier should be after the last '/'.
Something as below:
perf top -e cpu_core/cpu-cycles/P
Even for the non-hybrid or perf record, the /cpu-cycles:P/ format is
incorrect.
It looks like by design, not a bug.
$ perf record -e cpu/cycles:P/
event syntax error: 'cpu/cycles:P/'
\___ unknown term 'cycles:P' for pmu 'cpu'
valid terms:
event,pc,edge,any,offcore_rsp,ldlat,inv,umask,frontend,cmask,config,config1,config2,config3,name,period,freq,branch_type,time,call-graph,stack-size,no-inherit,inherit,max-stack,nr,no-overwrite,overwrite,driver-config,percore,aux-output,aux-sample-size,metric-id,raw,legacy-cache,hardware
Initial error:
event syntax error: 'cpu/cycles:P/'
\___ unknown term 'cycles:P' for pmu 'cpu'
$ perf record -e cpu/cycles/P
^C[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.695 MB perf.data (254 samples) ]
Thanks,
Kan
>
> valid terms: event,pc,edge,offcore_rsp,ldlat,inv,umask,frontend,cmask,config,config1,config2,config3,name,period,freq,branch_type,time,call-graph,stack-size,no-inherit,inherit,max-stack,nr,no-overwrite,overwrite,driver-config,percore,aux-output,aux-sample-size,metric-id,raw,legacy-cache,hardware
> Run 'perf list' for a list of valid events
>
> Usage: perf top [<options>]
>
> -e, --event <event> event selector. use 'perf list' to list available events
> root@...ora:~#
>
> So it seems its just 'perf top' breakage:
>
> root@...ora:~# perf top -e cpu_core/cpu-cycles/
> Error:
> The cpu_core/cpu-cycles/ event is not supported.
> root@...ora:~# perf top -e cpu_atom/cpu-cycles/
> Error:
> The cpu_atom/cpu-cycles/ event is not supported.
> root@...ora:~#
>
> I bisected this to:
>
> ⬢[acme@...lbox perf-tools-next]$ git bisect good
> 251aa040244a3b17068e4e6ec61f138d7e50681a is the first bad commit
> commit 251aa040244a3b17068e4e6ec61f138d7e50681a
> Author: Ian Rogers <irogers@...gle.com>
> Date: Thu Jun 1 01:29:53 2023 -0700
>
> perf parse-events: Wildcard most "numeric" events
>
> Numeric events are either raw events or those with ABI defined numbers
> matched by the lexer. PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE events
> should wildcard match on hybrid systems. So "cycles" should match each
> PMU type with an extended type, not just PERF_TYPE_HARDWARE.
>
> Change wildcard matching to add the event even if wildcard PMU
> scanning fails, there will be no extended type but this best matches
> previous behavior.
>
> Only set the extended type when the event type supports it and when
> perf_pmus__supports_extended_type is true. This new function returns
> true if >1 core PMU and avoids potential errors on older kernels.
>
> Modify evsel__compute_group_pmu_name using a helper
> perf_pmu__is_software to determine when grouping should occur. Try to
> use PMUs, and evsel__find_pmu, as being more dependable than
> evsel->pmu_name.
>
> Set a parse events error if a hardware term's PMU lookup fails, to
> provide extra diagnostics.
>
> Fixes: 8bc75f699c141420 ("perf parse-events: Support wildcards on raw events")
> Reported-by: Kan Liang <kan.liang@...ux.intel.com>
> Signed-off-by: Ian Rogers <irogers@...gle.com>
> Tested-by: Kan Liang <kan.liang@...ux.intel.com>
> Cc: Adrian Hunter <adrian.hunter@...el.com>
> Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
> Cc: Ingo Molnar <mingo@...hat.com>
> Cc: Jiri Olsa <jolsa@...nel.org>
> Cc: Mark Rutland <mark.rutland@....com>
> Cc: Namhyung Kim <namhyung@...nel.org>
> Cc: Peter Zijlstra <peterz@...radead.org>
> Cc: Ravi Bangoria <ravi.bangoria@....com>
> Cc: Rob Herring <robh@...nel.org>
> Cc: Thomas Richter <tmricht@...ux.ibm.com>
> Cc: Xing Zhengjun <zhengjun.xing@...ux.intel.com>
> Link: https://lore.kernel.org/r/20230601082954.754318-4-irogers@google.com
> Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
>
> tools/perf/util/parse-events.c | 104 +++++++++++++++++++++++++++++------------
> tools/perf/util/parse-events.y | 10 ++--
> tools/perf/util/pmu.c | 16 +++++++
> tools/perf/util/pmu.h | 5 ++
> tools/perf/util/pmus.c | 5 ++
> tools/perf/util/pmus.h | 1 +
> 6 files changed, 106 insertions(+), 35 deletions(-)
> ⬢[acme@...lbox perf-tools-next]$
>
> - Arnaldo
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