linux-kernel - Re: [PATCH 0/11] Per-bdi writeback flusher threads v9

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

Date:	Fri, 5 Jun 2009 20:18:15 -0400
From:	Chris Mason <chris.mason@...cle.com>
To:	Jan Kara <jack@...e.cz>
Cc:	Jens Axboe <jens.axboe@...cle.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org,
	tytso@....edu, david@...morbit.com, hch@...radead.org,
	yanmin_zhang@...ux.intel.com, richard@....demon.co.uk,
	damien.wyart@...e.fr
Subject: Re: [PATCH 0/11] Per-bdi writeback flusher threads v9

On Fri, Jun 05, 2009 at 11:14:38PM +0200, Jan Kara wrote:
> On Fri 05-06-09 21:15:28, Jens Axboe wrote:
> > On Fri, Jun 05 2009, Frederic Weisbecker wrote:
> > > The result with noop is even more impressive.
> > > 
> > > See: http://kernel.org/pub/linux/kernel/people/frederic/dbench-noop.pdf
> > > 
> > > Also a comparison, noop with pdflush against noop with bdi writeback:
> > > 
> > > http://kernel.org/pub/linux/kernel/people/frederic/dbench-noop-cmp.pdf
> > 
> > OK, so things aren't exactly peachy here to begin with. It may not
> > actually BE an issue, or at least now a new one, but that doesn't mean
> > that we should not attempt to quantify the impact.
>   What looks interesting is also the overall throughput. With pdflush we
> get to 2.5 MB/s + 26 MB/s while with per-bdi we get to 2.7 MB/s + 13 MB/s.
> So per-bdi seems to be *more* fair but throughput suffers a lot (which
> might be inevitable due to incurred seeks).
>   Frederic, how much does dbench achieve for you just on one partition
> (test both consecutively if possible) with as many threads as have those
> two dbench instances together? Thanks.

Is the graph showing us dbench tput or disk tput?  I'm assuming it is
disk tput, so bdi may just be writing less?

-chris

--
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/