From: Pavel Machek <pavel@ucw.cz>
To: OBATA Noboru <noboru.obata.ar@hitachi.com>
Cc: hyoshiok@miraclelinux.com, linux-kernel@vger.kernel.org
Subject: Re: Linux Kernel Dump Summit 2005
Date: Mon, 10 Oct 2005 10:45:35 +0200 [thread overview]
Message-ID: <20051010084535.GA2298@elf.ucw.cz> (raw)
In-Reply-To: <20051006.211718.74749573.noboru.obata.ar@hitachi.com>
Hi!
> FULL DUMP WITH COMPRESSION
> ==========================
>
> Those who still want a full dump, including me, are interested
> in dump compression. For example, the LKCD format (at least v7
> format) supports pagewise compression with the deflate
> algorithm. A dump analyze tool "crash" can transparently
> analyze the compressed dump file in this format.
>
> The compression will reduce the storage space at certain degree,
> and may also reduce the time if a dump process were I/O bounded.
I'd say that compression does not help much, it can only speed it up
twice. But...
>
> WHICH IS BETTER?
> ================
>
> I wrote a small compression tool for LKCD v7 format to see how
> effective the compression is, and it turned out that the time
> and size of compression were very much similar to that of gzip,
> not surprisingly.
>
> Compressing a 32GB dump file took about 40 minutes on Pentium 4
> Xeon 3.0GHz, which is not good enough because the dump without
> compression took only 5 minutes; eight times slower.
....you probably want to look at suspend2.net project. They have
special compressor aimed at compressing exactly this kind of data,
fast enough to be improvement.
Pavel
--
if you have sharp zaurus hardware you don't need... you know my address
next prev parent reply other threads:[~2005-10-10 8:45 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-09-21 11:55 Linux Kernel Dump Summit 2005 Hiro Yoshioka
2005-10-06 12:17 ` OBATA Noboru
2005-10-06 14:39 ` Hiro Yoshioka
2005-10-10 8:45 ` Pavel Machek [this message]
2005-10-12 8:28 ` OBATA Noboru
2005-10-12 9:02 ` Felix Oxley
2005-10-12 9:09 ` Pavel Machek
2005-10-12 9:56 ` Felix Oxley
2005-10-12 10:07 ` Pavel Machek
2005-10-12 18:03 ` Andy Isaacson
2005-10-12 22:34 ` Felix Oxley
2005-10-12 11:05 ` jerome lacoste
2005-10-12 21:10 ` Felix Oxley
2005-10-18 13:47 ` OBATA Noboru
2005-10-18 14:10 ` Hugh Dickins
2005-10-19 19:00 ` Theodore Ts'o
2005-10-27 7:48 ` OBATA Noboru
2005-10-11 0:49 ` Andrew Morton
2005-10-11 4:41 ` Hiro Yoshioka
2005-10-12 8:30 ` OBATA Noboru
2005-10-13 5:49 ` Maneesh Soni
2005-10-27 7:45 ` OBATA Noboru
2005-10-13 14:28 ` Troy Heber
2005-10-17 11:19 ` Takao Indoh
2005-10-18 13:48 ` OBATA Noboru
2005-10-19 3:17 ` Takao Indoh
2005-10-27 7:45 ` OBATA Noboru
2005-10-18 14:54 ` Carsten Otte
-- strict thread matches above, loose matches on Subject: below --
2005-10-14 9:19 hideki.takahashi
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