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Message-ID: <48B26E18.7020204@tauceti.net>
Date: Mon, 25 Aug 2008 10:32:24 +0200
From: RW <postgres@tauceti.net>
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To: pgsql-performance@postgresql.org
Subject: Re: Identifying the nature of blocking I/O
References: <20080822115243.GA10981@hyperion.scode.org>
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This matches not exactly the topic but it is sometimes helpfull.
If you've enabled I/O accounting and a kernel >= 2.6.20 (needs
to be compiled with

**CONFIG_TASKSTATS=y
CONFIG_TASK_DELAY_ACCT=y
CONFIG_TASK_XACCT=y
CONFIG_TASK_IO_ACCOUNTING=y
)

and sysstat package (>= 7.1.5) installed you can use "pidstat"
command which show's you the processes doing I/O in kb/sec.

Robert

**


Alexander Staubo wrote:
> On Mon, Aug 25, 2008 at 3:34 AM, Scott Carey <scott@richrelevance.com> wrote:
>   
>> DTrace is available now on MacOSX, Solaris 10, OpenSolaris, and FreeBSD.
>> Linux however is still in the dark ages when it comes to system monitoring,
>> especially with I/O.
>>     
>
> While that's true, newer 2.6 kernel versions at least have I/O
> accounting built in, something which only used to be available through
> the "atop" accounting kernel patch:
>
> $ cat /proc/22785/io
> rchar: 31928
> wchar: 138
> syscr: 272
> syscw: 4
> read_bytes: 0
> write_bytes: 0
> cancelled_write_bytes: 0
>
> Alexander.
>
>