From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: Isaku Yamahata <yamahata@valinux.co.jp>,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [Qemu-devel] Re: [PATCH 0/4] pci: interrupt status/interrupt disable support
Date: Thu, 26 Nov 2009 12:41:03 +0000 [thread overview]
Message-ID: <200911261241.04148.paul@codesourcery.com> (raw)
In-Reply-To: <20091126094811.GB26861@redhat.com>
> No, this would slow us down because these are per-pin.
> We need a sum of interrupts so that config space
> can be updated by a single command.
> Interrupts are a fastpath, extra loops there should be avoided.
It's really not that much of a fast path. Unless you're doing something
particularly obscure then even under heavy load you're unlikely to exceed a
few kHz. Compared to the average PIC implementation, and the overhead of the
actual CPU interrupt, I find it hard to believe that looping over precisely 4
entries has any real performance hit.
Paul
next prev parent reply other threads:[~2009-11-26 12:41 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-25 16:58 [Qemu-devel] [PATCH 0/4] pci: interrupt status/interrupt disable support Michael S. Tsirkin
2009-11-26 3:21 ` [Qemu-devel] " Isaku Yamahata
2009-11-26 9:48 ` Michael S. Tsirkin
2009-11-26 12:41 ` Paul Brook [this message]
2009-11-26 12:59 ` Michael S. Tsirkin
2009-11-26 13:21 ` Paul Brook
2009-11-26 13:34 ` Michael S. Tsirkin
2009-11-26 10:38 ` Michael S. Tsirkin
2009-11-26 13:11 ` Michael S. Tsirkin
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