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From: Jens Axboe <jens.axboe@oracle.com>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	lkml - Kernel Mailing List <linux-kernel@vger.kernel.org>,
	virtualization <virtualization@lists.osdl.org>
Subject: Re: [PATCH 7/8] lguest: trivial guest block driver
Date: Mon, 12 Feb 2007 16:01:25 +0100	[thread overview]
Message-ID: <20070212150125.GM3999@kernel.dk> (raw)
In-Reply-To: <1171264167.10409.62.camel@localhost.localdomain>

On Mon, Feb 12 2007, Rusty Russell wrote:
> On Mon, 2007-02-12 at 06:32 +0100, Jens Axboe wrote:
> > On Mon, Feb 12 2007, Rusty Russell wrote:
> > > On Mon, 2007-02-12 at 05:43 +0100, Jens Axboe wrote:
> > > > Here you map the entire request (lets call that segment A..Z), but
> > > > end_request() only completes the first chunk of the request. So
> > > > elv_next_request() will retrieve the same request again, and you'll then
> > > > map B..Z and repeat that transfer. So unless I'm missing some other part
> > > > here (just read it over quickly), you are re-doing large parts of a
> > > > merged request several times.
> 
> virtbench before:
> 	Time to read from disk (256 kB): 18654562 nsec
> After:
> 	Time to read from disk (256 kB): 8018468 nsec
> 
> Thanks Jens!!

My pleasure, it's not often you get to make that big a performance
improvement with just a little few lines of change :-)

I guess you'll take changes to make this driver queuing as well? It's
pretty important for good guest io performance as well.

-- 
Jens Axboe


  reply	other threads:[~2007-02-12 15:01 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2007-02-12  3:32 [PATCH 1/7] cleanup: paravirt unhandled fallthrough Rusty Russell
2007-02-12  3:33 ` [PATCH 2/7] cleanup: Initialize esp0 properly all the time Rusty Russell
2007-02-12  3:34   ` [PATCH 3/7] cleanup: Make hvc_console.c compile on non-PowerPC Rusty Russell
2007-02-12  3:35     ` [PATCH 4/7] cleanup: Move mce_disabled to asm/mce.h Rusty Russell
2007-02-12  3:36       ` [PATCH 5/7] cleanup: Rename cpu_gdt_descr and remove extern declaration from smpboot.c Rusty Russell
2007-02-12  3:37         ` [PATCH 6/7] cleanup: Remove extern declaration from mm/discontig.c, put in header Rusty Russell
2007-02-12  3:39           ` [PATCH 7/7] cleanup: make disable_acpi() valid w/o CONFIG_ACPI Rusty Russell
2007-02-12  3:41             ` [PATCH 1/2] lguest preparation: EXPORT_SYMBOL_GPL 5 functions Rusty Russell
2007-02-12  3:42               ` [PATCH 2/2] lguest preparation: expose futex infrastructure: get_futex_key, get_key_refs and drop_key_refs Rusty Russell
2007-02-12  3:44                 ` [PATCH 1/8] lguest: Kconfig and headers Rusty Russell
2007-02-12  3:46                   ` [PATCH 2/8] lguest: the host code (lg.ko) Rusty Russell
2007-02-12  3:48                     ` [PATCH 3/8] lguest: Guest code Rusty Russell
2007-02-12  3:50                       ` [PATCH 4/8] lguest: Makefile Rusty Russell
2007-02-12  3:52                         ` [PATCH 5/8] lguest: trivial guest network driver Rusty Russell
2007-02-12  3:53                           ` [PATCH 6/8] lguest: trivial guest console driver Rusty Russell
2007-02-12  3:54                             ` [PATCH 7/8] lguest: trivial guest block driver Rusty Russell
2007-02-12  3:55                               ` [PATCH 8/8] lguest: documentatation and example launcher Rusty Russell
2007-02-12  4:43                               ` [PATCH 7/8] lguest: trivial guest block driver Jens Axboe
2007-02-12  5:27                                 ` Rusty Russell
2007-02-12  5:32                                   ` Jens Axboe
2007-02-12  5:33                                     ` Jens Axboe
2007-02-12  7:09                                     ` Rusty Russell
2007-02-12  7:09                                       ` Rusty Russell
2007-02-12 15:01                                       ` Jens Axboe [this message]
2007-02-13  0:25                                         ` Rusty Russell
2007-02-13  0:25                                           ` Rusty Russell
2007-02-13  0:44                                           ` Jens Axboe
2007-02-12 15:55                           ` [PATCH 5/8] lguest: trivial guest network driver Herbert Xu
2007-02-13  2:15                             ` Rusty Russell
2007-02-13 14:06                               ` Herbert Xu
2007-02-14  4:47                                 ` Rusty Russell
2007-02-14 13:57                                   ` Herbert Xu
2007-02-14 23:00                                     ` Rusty Russell
2007-02-12 16:02                   ` [PATCH 1/8] lguest: Kconfig and headers James Morris
2007-02-13  5:09             ` [PATCH 7/7] cleanup: make disable_acpi() valid w/o CONFIG_ACPI Len Brown
2007-02-12  9:16         ` [PATCH 5/7] cleanup: Rename cpu_gdt_descr and remove extern declaration from smpboot.c Zachary Amsden

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