[RFC PATCH 0/4] makedumpfile: cyclic processing to keep memory consumption.
d.hatayama at jp.fujitsu.com
Mon Jun 4 21:10:46 EDT 2012
From: Maxim Uvarov <muvarov at gmail.com>
Subject: Re: [RFC PATCH 0/4] makedumpfile: cyclic processing to keep memory consumption.
Date: Mon, 4 Jun 2012 12:29:07 +0400
> 2012/6/4 Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp>
>> Hello Maxim,
>> On Thu, 31 May 2012 10:50:39 +0400
>> Maxim Uvarov <muvarov at gmail.com> wrote:
>> After received your mail, I measured executing time with the patch below.
>> The result below was measured in 5GB memory machine.
>> a. makedumpfile -Kcd31
>> excluding time: 6.55 [sec]
>> writing time: 5.89 [sec]
>> b. makedumpfile -cd31
>> excluding time: 0.21 [sec]
>> writing time: 5.82 [sec]
>> I don't think this result is good, the prototype has some points to be
>> improved for performance.
>> (e.g. buffer size, the way to exclude free pages, etc...)
>> However, I think getting a bit of speed down can't be helped to keep
>> memory consumption.
> I'm asking because I have machines with several TBs of ram. And filtering
> and saving data from vmcore takes long time. (more then 30 minutes). I
> wonder if somebody already work on performance. Probably we can do SMP
I'm now benchmarking for three kinds of pralell compressions: no
compression, lzo and snappy. I'll post its result after completing it,
by Friday? if possible.
Also I'll soon post a patch for filtering free pages in constant time
based on mem_map, just a small extension of the patch Kumagai-san
posted previously, by which filtering score for -Kcd31 above would be
improved so much; it now repeats tracing free_list (memory size /
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