Re: [patch] Performance Counters for Linux, v2

From: Corey J Ashford
Date: Mon Dec 08 2008 - 03:33:03 EST


linux-kernel-owner@xxxxxxxxxxxxxxx wrote on 12/07/2008 05:22:12 PM:
[snip]
>
> The other big change is the support of virtual task counters via counter

> scheduling: a task can specify more counters than there are on the CPU,
> the kernel will then schedule the counters periodically to spread out hw

> resources. So for example if a task starts 6 counters on a CPU that has
> only two hardware counters, it still gets this output:
>
> counter[0 cycles ]: 5204680573 , delta: 1733680843
events
> counter[1 instructions ]: 1364468045 , delta: 454818351
events
> counter[2 cache-refs ]: 12732 , delta: 4399
events
> counter[3 cache-misses ]: 1009 , delta: 336
events
> counter[4 branch-instructions ]: 125993304 , delta: 42006998
events
> counter[5 branch-misses ]: 1946 , delta: 649
events
>

Hello Ingo,

I posted some questions about this capability in your proposal on LKML,
but I wasn't able to get the reply threaded in properly. Could you take a
look at this post, please?

http://lkml.org/lkml/2008/12/5/299

Thanks for your consideration,

- Corey

Corey Ashford
Software Engineer
IBM Linux Technology Center, Linux Toolchain
Beaverton, OR
503-578-3507
cjashfor@xxxxxxxxxx
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