linux-kernel - Re: Strange write starvation on 2.6.17 (and other) kernels

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <17641.3304.948174.971955@cse.unsw.edu.au>
Date:	Mon, 21 Aug 2006 11:31:20 +1000
From:	Neil Brown <neilb@...e.de>
To:	"Miquel van Smoorenburg" <miquels@...tron.nl>
Cc:	linux-kernel@...r.kernel.org,
	Andrzej Szymanski <szymans@....edu.pl>
Subject: Re: Strange write starvation on 2.6.17 (and other) kernels

On Thursday August 17, miquels@...tron.nl wrote:
> In article <44E0A69C.5030103@....edu.pl>,
> Andrzej Szymanski  <szymans@....edu.pl> wrote:
> >I've encountered a strange problem - if an application is sequentially 
> >writing a large file on a busy machine, a single write() of 64KB may 
> >take even 30 seconds. But if I do fsync() after each write() the maximum 
> >time of write()+fsync() is about 0.5 second (the overall performance is, 
> >of course, degraded).
> 
> I'm seeing something similar.

Can you report the contents of /proc/meminfo before, during, and after
the long pause?
I'm particularly interested in MemTotal, Dirty, and Writeback, but the
others are of interest too.

Thanks,
NeilBrown
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/