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Date: Wed, 9 Dec 2015 09:15:04 -0800
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Subject: Re: [Questions] perf c2c: What's the current status of perf c2c?
From: Stephane Eranian <eranian@google.com>
To: Andi Kleen <andi@firstfloor.org>
Cc: Peter Zijlstra <peterz@infradead.org>, Jiri Olsa <jolsa@redhat.com>,
        Yunlong Song <yunlong.song@huawei.com>,
        Don Zickus <dzickus@redhat.com>, David Ahern <dsahern@gmail.com>,
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Hi,

On Wed, Dec 9, 2015 at 8:58 AM, Andi Kleen <andi@firstfloor.org> wrote:
>> > the plan for me is to to use it some more to prove it's useful
>> > and kick it to be merged with perf at some point
>>
>> So I never really liked the c2c tool because it was so narrowly
>> focussed, it only works on NUMA thingies IIRC.
>
> It should work on all systems with an Intel Core (not Atom)
>
> However it was never clear to me if the tool was any better
> than simply sampling for
>
> mem_load_uops_l3_hit_retired.xsnp_hitm:pp    (local socket)
> mem_load_uops_l3_miss_retired.remote_hitm:pp (remote socket)
>
> which gives you instructions that reference bouncing cache lines.
>
If I recall the c2c tool is giving you more than the bouncing line. It shows you
the offset inside the line and the participating CPUs.