From: Alexei Starovoitov <ast@plumgrid.com>
To: Kaixu Xia <xiakaixu@huawei.com>,
davem@davemloft.net, daniel@iogearbox.net, acme@kernel.org,
mingo@redhat.com, a.p.zijlstra@chello.nl,
masami.hiramatsu.pt@hitachi.com, jolsa@kernel.org
Cc: linux-kernel@vger.kernel.org, wangnan0@huawei.com, pi3orama@163.com
Subject: Re: [RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs to access hardware PMU counter
Date: Fri, 28 Aug 2015 18:28:33 -0700 [thread overview]
Message-ID: <55E10AC1.1000706@plumgrid.com> (raw)
In-Reply-To: <1440672142-89311-1-git-send-email-xiakaixu@huawei.com>
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.
next prev parent reply other threads:[~2015-08-29 1:28 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-27 10:42 [RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs to access hardware PMU counter Kaixu Xia
2015-08-27 10:42 ` [RFC PATCH 1/4] bpf tools: Add bpf_update_elem() and perf_event_open() for common bpf operations Kaixu Xia
2015-08-27 10:42 ` [RFC PATCH 2/4] bpf tools: Collect BPF_MAP_TYPE_PERF_EVENT_ARRAY map definitions from 'maps' section Kaixu Xia
2015-08-27 10:42 ` [RFC PATCH 3/4] bpf tools: Save the perf event fds from "maps" sections to 'struct bpf_object' Kaixu Xia
2015-08-27 10:42 ` [RFC PATCH 4/4] bpf tools: Enable/disable the perf events stored in " Kaixu Xia
2015-08-29 1:28 ` Alexei Starovoitov [this message]
2015-08-29 2:14 ` [RFC PATCH 0/4] perf tools: Use the new ability of eBPF programs to access hardware PMU counter xiakaixu
2015-08-29 2:42 ` Alexei Starovoitov
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