linux-kernel - Re: [RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs to access hardware PMU counter

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: <55E10AC1.1000706@plumgrid.com>
Date:	Fri, 28 Aug 2015 18:28:33 -0700
From:	Alexei Starovoitov <ast@...mgrid.com>
To:	Kaixu Xia <xiakaixu@...wei.com>, davem@...emloft.net,
	daniel@...earbox.net, acme@...nel.org, mingo@...hat.com,
	a.p.zijlstra@...llo.nl, masami.hiramatsu.pt@...achi.com,
	jolsa@...nel.org
Cc:	linux-kernel@...r.kernel.org, wangnan0@...wei.com, pi3orama@....com
Subject: Re: [RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs
 to access hardware PMU counter

On 8/27/15 3:42 AM, Kaixu Xia wrote:
> An example is pasted at the bottom of this cover letter. In that example,
> we can get the cpu_cycles and exception taken in sys_write.
>
>   $ cat /sys/kernel/debug/tracing/trace_pipe
>   $ ./perf record --event perf-bpf.o ls
> 	...
>               cat-1653  [003] d..1 88174.613854: : ente:  CPU-3	cyc:48746333	exc:84
>               cat-1653  [003] d..2 88174.613861: : exit:  CPU-3	cyc:48756041	exc:84

nice. probably more complex example that computes the delta of the pmu
counters on the kernel side would be even more interesting.
Do you think you can extend 'perf stat' with a flag that does
stats collection for a given kernel or user function instead of the
whole process ?
Then we can use perf record/report to figure out hot functions and
follow with 'perf stat -f my_hot_func my_process' to drill into
particular function stats.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/