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From: Arthur Marsh <arthur.marsh@internode.on.net>
To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Clemens Ladisch <cladisch@googlemail.com>,
	alsa-user@lists.sourceforge.net, linux-kernel@vger.kernel.org,
	Mel Gorman <mel@csn.ul.ie>
Subject: Re: [Alsa-user] new source of MIDI playback slow-down identified - 5a03b051ed87e72b959f32a86054e1142ac4cf55 thp: use compaction in kswapd for GFP_ATOMIC order > 0
Date: Sun, 27 Feb 2011 19:18:00 +1030	[thread overview]
Message-ID: <4D6A0FC0.1000307@internode.on.net> (raw)
In-Reply-To: <20110226064339.GC19630@random.random>



Andrea Arcangeli wrote, on 26/02/11 17:13:
> On Thu, Feb 24, 2011 at 02:54:05AM +0100, Andrea Arcangeli wrote:
>> Ok so tomorrow I'll get all results on these 3 kernels (
>> compaction-kswapd-3+compaction_alloc_lowlat-2 vs
>> compaction-no-kswapd-3+compaction_alloc_lowlat-2 vs
>> compaction_alloc_lowlat2) on network server load, where throughout is
>> measured in addition to latency. Then we'll have a better picture to
>
> Latency is still lowest with compaction-no-kswapd-3. compaction_alloc
> still is at the top of the profiling with
> compaction-kswapd-3+compaction_alloc_lowlat-2. However
> compaction-kswapd-3 reduced the overhead somewhat but not enough to be
> as fast as with compaction-no-kswapd-3 (even if much better than
> before).
>
> So we should apply compaction-no-kswapd-3 to 2.6.38 I think.

I built a kernel based against git head of around 0800 UTC Saturday 
2011-02-26 plus compaction-no-kswapd-3 (Andrea's) and 
compaction_alloc_lowlat-2 (Mel's) patches.

The the latency performance for MIDI playback is excellent and kswap0 
has reported 100 seconds of CPU time in 22 hours of the kernel kernel 
running.

However, I am now battling against the kernel freeing up memory when 
using icedove/thunderbird. top is reporting 74 MiB resident, 418 MiB 
virtual, and as I pause typing to watch top output, free RAM has gone up 
to 50 MiB and I'm stuck waiting for parts of icedove to swap back in so 
that I can get a response from my input (either scrolling a message when 
reading it or composing a message, where I am left waiting for the text 
that I typed to appear).

Normally in this machine with only 384 MiB RAM and (say) 2.6.35-2.6.37 
kernels, free RAM will hover around the 5 MiB mark when lots of 
applications are open. I may wait when switching from one running 
application to another for it to respond, but once I am using that 
particular application it sufficiently responsive not to be annoying.

The aggressive reclamation of RAM by the kernel I built around 0800 UTC 
Saturday is working against the application currently in focus.

I will try Andrea's and Mel's patches built against 2.6.36-rc6 over the 
next several hours to see how that compares.

Arthur.

  reply	other threads:[~2011-02-27  8:48 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <g0ia38-jj6.ln1@ppp121-45-136-118.lns11.adl6.internode.on.net>
2011-02-22  7:37 ` [Alsa-user] new source of MIDI playback slow-down identified - 5a03b051ed87e72b959f32a86054e1142ac4cf55 thp: use compaction in kswapd for GFP_ATOMIC order > 0 Clemens Ladisch
2011-02-22  7:46   ` Arthur Marsh
2011-02-22 13:40   ` Andrea Arcangeli
2011-02-22 16:15     ` Andrea Arcangeli
2011-02-22 16:59       ` Mel Gorman
2011-02-22 17:08         ` Andrea Arcangeli
2011-02-22 17:37           ` Mel Gorman
2011-02-22 17:47       ` Arthur Marsh
2011-02-22 19:43         ` Andrea Arcangeli
2011-02-23  9:15           ` Mel Gorman
2011-02-23 11:41             ` Arthur Marsh
2011-02-23 13:50               ` Clemens Ladisch
2011-02-23 17:01               ` Mel Gorman
2011-02-23 17:40                 ` Andrea Arcangeli
2011-02-23 16:24         ` Andrea Arcangeli
2011-02-23 16:36           ` Andrea Arcangeli
2011-02-23 16:40             ` Andrea Arcangeli
2011-02-23 16:47               ` Andrea Arcangeli
2011-02-23 16:55           ` Andrea Arcangeli
2011-02-23 20:07             ` Arthur Marsh
2011-02-23 21:25               ` Andrea Arcangeli
2011-02-23 21:55                 ` Arthur Marsh
2011-02-23 23:59                   ` Andrea Arcangeli
2011-02-24  1:40                     ` Arthur Marsh
2011-02-24  1:54                       ` Andrea Arcangeli
2011-02-26  6:43                         ` Andrea Arcangeli
2011-02-27  8:48                           ` Arthur Marsh [this message]
2011-02-23 17:10           ` Mel Gorman
2011-02-23 17:27             ` Andrea Arcangeli
2011-02-23 17:44               ` Mel Gorman
2011-02-23 18:14                 ` Andrea Arcangeli

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