linux-kernel - RE: [patch, resend] x86, perf_counter, bts: optimize BTS overflow handling

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Date:	Tue, 15 Sep 2009 12:18:23 +0100
From:	"Metzger, Markus T" <markus.t.metzger@...el.com>
To:	Peter Zijlstra <a.p.zijlstra@...llo.nl>
CC:	"mingo@...e.hu" <mingo@...e.hu>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"hpa@...or.com" <hpa@...or.com>,
	"markus.t.metzger@...il.com" <markus.t.metzger@...il.com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [patch, resend] x86, perf_counter, bts: optimize BTS overflow
 handling

>-----Original Message-----
>From: Peter Zijlstra [mailto:a.p.zijlstra@...llo.nl]
>Sent: Tuesday, September 15, 2009 1:12 PM


>> Restructure perf_counter sampling into sample creation and sample
>> output.
>> Prepare a single reference sample for BTS sampling and update the from
>> and to address fields when draining the BTS buffer.
>> Drain the entire BTS buffer between a single perf_output_begin() /
>> perf_output_end() pair.
>
>Generally looks very nice, one thing though, why did you take regs out
>of perf_sample_data, now you get to pass around one extra param..


That is to make perf_sample_data describe the sample directly.

The regs are used to create the sample; they're not needed once
the sample has been created.


>> CC: Peter Zijlstra <a.p.zijlstra@...llo.nl>
>> Signed-off-by: Markus Metzger <markus.t.metzger@...el.com>
>> ---
>>  arch/x86/kernel/cpu/perf_counter.c |   60 	37 +	23 -	0 !
>>  include/linux/perf_counter.h       |   68 	64 +	4 -	0 !
>>  kernel/perf_counter.c              |  306 	161 +	145 -	0 !
>>  3 files changed, 262 insertions(+), 172 deletions(-)
>
>What is that diffstat thing? I always get things like:
>
> kernel/sched.c |    4 ++--
> 1 files changed, 2 insertions(+), 2 deletions(-)
>

I'm using QUILT_DIFFSTAT_OPTS="-f0".

regards,
markus.
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