From: David Miller <davem@davemloft.net>
To: matthew@wil.cx
Cc: ebiederm@xmission.com, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, grundler@parisc-linux.org,
mingo@elte.hu, tglx@linutronix.de, jgarzik@pobox.com,
linux-ide@vger.kernel.org, suresh.b.siddha@intel.com,
benh@kernel.crashing.org, jbarnes@virtuousgeek.org,
rdunlap@xenotime.net, mtk.manpages@gmail.com
Subject: Re: Multiple MSI, take 3
Date: Fri, 11 Jul 2008 03:32:42 -0700 (PDT) [thread overview]
Message-ID: <20080711.033242.58168774.davem@davemloft.net> (raw)
In-Reply-To: <20080711102326.GR14894@parisc-linux.org>
From: Matthew Wilcox <matthew@wil.cx>
Date: Fri, 11 Jul 2008 04:23:26 -0600
> On Fri, Jul 11, 2008 at 03:06:33AM -0700, Eric W. Biederman wrote:
> > So unless the performance of the AHCI is better by a huge amount I don't
> > see the point, and even then I am extremely sceptical.
>
> I don't have performance numbers yet, but surely you can see that
> avoiding a register read in the interrupt path is a large win?
Such overhead is going to be amortized.
AHCI is not like networking where we have lots of very small
transactions to deal with, and therefore the per-IRQ overhead can
begin to dominate.
Therefore, like Eric, I think workng on multiple MSI is a very dubious
usage of one's time. But, it's your time, so use it how you wish :)
next prev parent reply other threads:[~2008-07-11 10:32 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-07-11 0:57 Multiple MSI, take 3 Matthew Wilcox
2008-07-11 0:59 ` [PATCH] PCI MSI: Replace 'type' with 'is_msix' Matthew Wilcox
2008-07-11 0:59 ` [PATCH] PCI: Add support for multiple MSI Matthew Wilcox
2008-07-11 8:28 ` Hidetoshi Seto
2008-07-11 9:45 ` Matthew Wilcox
2008-07-12 3:45 ` Benjamin Herrenschmidt
2008-07-11 1:00 ` [PATCH] Rewrite MSI-HOWTO Matthew Wilcox
2008-09-26 6:42 ` Grant Grundler
2008-07-11 1:00 ` [PATCH] AHCI: Request multiple MSIs Matthew Wilcox
2008-07-11 1:00 ` [PATCH] x86-64: Support for " Matthew Wilcox
2008-07-11 4:50 ` Kenji Kaneshige
2008-07-11 8:50 ` Matthew Wilcox
2008-07-14 1:08 ` Kenji Kaneshige
2008-07-11 10:06 ` Multiple MSI, take 3 Eric W. Biederman
2008-07-11 10:23 ` Matthew Wilcox
2008-07-11 10:32 ` David Miller [this message]
2008-07-11 10:41 ` Matthew Wilcox
2008-07-11 11:05 ` Eric W. Biederman
2008-07-11 11:34 ` Eric W. Biederman
2008-07-11 12:17 ` Matthew Wilcox
2008-07-11 15:10 ` Matthew Wilcox
2008-07-11 21:59 ` Suresh Siddha
2008-07-11 22:59 ` Eric W. Biederman
2008-07-11 23:15 ` Suresh Siddha
2008-07-11 23:59 ` Eric W. Biederman
2008-07-12 3:52 ` Benjamin Herrenschmidt
2008-07-12 4:41 ` Eric W. Biederman
2008-07-12 7:36 ` Benjamin Herrenschmidt
2008-07-13 22:30 ` Eric W. Biederman
2008-07-13 22:44 ` Benjamin Herrenschmidt
2008-07-13 23:29 ` Eric W. Biederman
2008-07-14 0:17 ` Benjamin Herrenschmidt
2008-07-14 0:44 ` David Miller
2008-07-14 2:03 ` Eric W. Biederman
2008-07-14 3:19 ` David Miller
2008-09-26 5:30 ` Jike Song
2008-09-27 19:04 ` Matthew Wilcox
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