linux-kernel - Re: [RFC/PATCHSET 0/9] perf record: Implement BPF sample filter (v4)

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <479da7ad-66ba-870e-a2ac-c1378e2f452b@amd.com>
Date:   Mon, 13 Mar 2023 21:21:33 +0530
From:   Ravi Bangoria <ravi.bangoria@....com>
To:     Namhyung Kim <namhyung@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...nel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Song Liu <song@...nel.org>,
        Stephane Eranian <eranian@...gle.com>,
        Leo Yan <leo.yan@...aro.org>,
        James Clark <james.clark@....com>, Hao Luo <haoluo@...gle.com>,
        LKML <linux-kernel@...r.kernel.org>,
        linux-perf-users@...r.kernel.org, bpf@...r.kernel.org,
        Ravi Bangoria <ravi.bangoria@....com>
Subject: Re: [RFC/PATCHSET 0/9] perf record: Implement BPF sample filter (v4)

>> However, if I add "mem_lvl == l1" (or l2 / ram) in the filter, I see mostly
>> all samples are getting lost:
>>
>>   $ sudo ./perf record -d -e ibs_op//p --filter 'mem_op == load, mem_lvl == l1' -c 100000 ~/test
>>   [ perf record: Woken up 1 times to write data ]
>>   [ perf record: Captured and wrote 0.019 MB perf.data ]
>>
>>   $ sudo ./perf report --stat | grep SAMPLE
>>     LOST_SAMPLES events:          1  ( 0.8%)
>>     LOST_SAMPLES events:     136332
>>
>> What am I missing?
> 
> It seems IBS PMU doesn't set the mem_lvlnum field in the data source.
> As I said in the patch 7, 'mem_lvl' actually uses mem_lvlnum fields
> instead of mem_lvl because it's preferred according to the comment in
> the UAPI header.
> 
> /*
>  * PERF_MEM_LVL_* namespace being depricated to some extent in the
>  * favour of newer composite PERF_MEM_{LVLNUM_,REMOTE_,SNOOPX_} fields.
>  * Supporting this namespace inorder to not break defined ABIs.
>  *
>  * memory hierarchy (memory level, hit or miss)
>  */
> 
> I'll post a patch to set it separately.

Got it. I saw your patch, will review it.

Thanks,
Ravi