From: Gleb Natapov <gleb@redhat.com>
To: Alexander Graf <agraf@suse.de>
Cc: "Richard W.M. Jones" <rjones@redhat.com>,
Avi Kivity <avi@redhat.com>, qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] Slow kernel/initrd loading via fw_cfg; Was Re: Hack integrating SeaBios / LinuxBoot option rom with QEMU trace backends
Date: Tue, 11 Oct 2011 15:17:36 +0200 [thread overview]
Message-ID: <20111011131736.GY30105@redhat.com> (raw)
In-Reply-To: <2DB3FD25-4BF7-4F82-9A62-49A6891316B3@suse.de>
On Tue, Oct 11, 2011 at 03:14:52PM +0200, Alexander Graf wrote:
> > rep/ins is effectively equivalent to DMA except in how it's handled within QEMU.
>
> No, DMA has a lot bigger granularities in kvm/user interaction. We can easily DMA a 50MB region with a single kvm/user exit. For PIO we can at most do page granularity.
>
Not only granularity, but double copy too. May be Anthony is referring
to real HW in which case I also do not see how it can be true since one
operation is synchronous and another is not.
--
Gleb.
next prev parent reply other threads:[~2011-10-11 13:17 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-10-10 17:08 [Qemu-devel] Hack integrating SeaBios / LinuxBoot option rom with QEMU trace backends Daniel P. Berrange
2011-10-10 18:53 ` Anthony Liguori
2011-10-10 19:01 ` Alexander Graf
2011-10-11 8:23 ` [Qemu-devel] Slow kernel/initrd loading via fw_cfg; Was " Daniel P. Berrange
2011-10-11 8:43 ` Richard W.M. Jones
2011-10-11 9:15 ` Avi Kivity
2011-10-11 9:19 ` Alexander Graf
2011-10-11 9:26 ` Avi Kivity
2011-10-11 9:38 ` Alexander Graf
2011-10-11 9:49 ` Avi Kivity
2011-10-11 9:56 ` Gleb Natapov
2011-10-11 9:59 ` Avi Kivity
2011-10-11 10:28 ` Gleb Natapov
2011-10-11 13:12 ` Anthony Liguori
2011-10-11 13:14 ` Alexander Graf
2011-10-11 13:17 ` Gleb Natapov [this message]
2011-10-11 13:19 ` Anthony Liguori
2011-10-11 13:23 ` Avi Kivity
2011-10-11 13:24 ` Gleb Natapov
2011-10-11 13:29 ` Anthony Liguori
2011-10-11 13:45 ` Avi Kivity
2011-10-11 13:58 ` Anthony Liguori
2011-10-11 14:01 ` Daniel P. Berrange
2011-10-11 14:33 ` Anthony Liguori
2011-10-11 14:34 ` Alexander Graf
2011-10-11 14:36 ` Daniel P. Berrange
2011-10-11 9:50 ` Gleb Natapov
2011-10-11 9:55 ` Avi Kivity
2011-10-11 13:17 ` Anthony Liguori
2011-10-11 13:22 ` Gleb Natapov
2011-10-15 14:19 ` Kevin O'Connor
2011-10-11 9:27 ` Daniel P. Berrange
2011-10-11 9:39 ` Avi Kivity
2011-10-11 9:49 ` Daniel P. Berrange
2011-10-11 9:50 ` Avi Kivity
2011-10-11 10:09 ` Daniel P. Berrange
2011-10-15 10:00 ` Blue Swirl
2011-10-15 16:16 ` Richard W.M. Jones
2011-10-16 17:20 ` Lluís Vilanova
2011-10-11 9:08 ` [Qemu-devel] " Avi Kivity
2011-10-11 9:18 ` Daniel P. Berrange
2011-10-11 9:35 ` Avi Kivity
2011-10-10 23:57 ` Kevin O'Connor
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