[pulseaudio-discuss] [RFC PATCH] alsa-sink: Reduce hardware pointer update syscalls

[David Henningsson]

On 2014-09-30 10:11, Alexander E. Patrakov wrote:
> 30.09.2014 12:43, David Henningsson wrote:
>>
>>
>> On 2014-09-29 16:33, Laurențiu Nicola wrote:
>>> If nobody tried it, I might test the patch on my USB DAC. The problem is
>>> that I'm not sure what's the best way to benchmark the playback. Do you
>>> have some tips on that?
>>
>> Run "top" in a low-latency playback scenario, that should be enough. You
>> might want to verify (e g with pactl) that you end up with the same
>> latency both with and without the patch.
>>
>> Maybe others have more accurate methods to measure CPU consumption.
>
> I used "perf". Please see this message:
>
> http://lists.freedesktop.org/archives/pulseaudio-discuss/2014-September/021745.html

I'm hesitant to using perf, at least in that way. The result will 
include the entire startup phase, include how we probe the devices, read 
configuration files and so on. That impact is significant, unless you 
run your test for a very long time.

I wonder if there's a way we can tell perf to skip the first 10 seconds, 
or so? That way the test would be more accurate.

-- 
David Henningsson, Canonical Ltd.
https://launchpad.net/~diwic