From: Nick Piggin <npiggin@suse.de>
To: Christoph Hellwig <hch@lst.de>
Cc: Vivek Goyal <vgoyal@redhat.com>, Jens Axboe <axboe@kernel.dk>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: trying to understand READ_META, READ_SYNC, WRITE_SYNC & co
Date: Sat, 26 Jun 2010 20:10:45 +1000 [thread overview]
Message-ID: <20100626101045.GJ29809@laptop> (raw)
In-Reply-To: <20100626092759.GA25896@lst.de>
On Sat, Jun 26, 2010 at 11:27:59AM +0200, Christoph Hellwig wrote:
> On Sat, Jun 26, 2010 at 07:25:56PM +1000, Nick Piggin wrote:
> > Biggest thing is multiple small files operations like on the same
> > directory. Best case I measured back when doing AS io scheduler
> > versus deadline was about 100x improvement on a uncached kernel
> > grep workload when competing with a streaming writeout (the writeout
> > probably ended up going somewhat slower naturally, but it is fairer).
>
> As I mentioned below I absolutely see the case for reads. A normal
> grep basically is a dependent read kind of workload. For for writes
> it should either be O_SYNC-style workloads or batched I/O.
Sorry I missed that. OK well that may be true. One would hope
it was benchmarked before being merged.
But I'm sure apps can submit fsyncs much faster than once per
few ms, like small database transactions.
next prev parent reply other threads:[~2010-06-26 10:10 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-06-21 9:48 trying to understand READ_META, READ_SYNC, WRITE_SYNC & co Christoph Hellwig
2010-06-21 10:04 ` Jens Axboe
2010-06-21 11:04 ` Christoph Hellwig
2010-06-21 18:56 ` Jens Axboe
2010-06-21 19:14 ` Christoph Hellwig
2010-06-21 19:16 ` Jens Axboe
2010-06-21 19:20 ` Christoph Hellwig
2010-06-21 21:36 ` Vivek Goyal
2010-06-23 10:01 ` Christoph Hellwig
2010-06-24 1:44 ` Vivek Goyal
2010-06-25 11:03 ` Christoph Hellwig
2010-06-26 3:35 ` Vivek Goyal
2010-06-26 10:05 ` Christoph Hellwig
2010-06-26 11:20 ` Jens Axboe
2010-06-26 11:56 ` Christoph Hellwig
2010-06-27 15:44 ` Jeff Moyer
2010-06-29 9:06 ` Corrado Zoccolo
2010-06-29 12:30 ` Vivek Goyal
2010-06-30 15:30 ` Corrado Zoccolo
2010-06-26 9:25 ` Nick Piggin
2010-06-26 9:27 ` Christoph Hellwig
2010-06-26 10:10 ` Nick Piggin [this message]
2010-06-26 10:16 ` Christoph Hellwig
2010-06-21 18:52 ` Jeff Moyer
2010-06-21 18:58 ` Jens Axboe
2010-06-21 19:08 ` Jeff Moyer
2010-06-23 9:26 ` Christoph Hellwig
2010-06-21 20:25 ` Vivek Goyal
2010-06-23 10:02 ` Christoph Hellwig
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