From: Avi Kivity <avi@redhat.com>
To: Alexander Graf <agraf@suse.de>
Cc: Gleb Natapov <gleb@redhat.com>,
seabios@seabios.org, qemu-devel <qemu-devel@nongnu.org>,
"Richard W.M. Jones" <rjones@redhat.com>
Subject: Re: [Qemu-devel] Hack integrating SeaBios / LinuxBoot option rom with QEMU trace backends
Date: Tue, 11 Oct 2011 11:08:33 +0200 [thread overview]
Message-ID: <4E940791.1070600@redhat.com> (raw)
In-Reply-To: <A80BA8A9-385C-4B4A-93B7-0F34A0035AA9@suse.de>
On 10/10/2011 09:01 PM, Alexander Graf wrote:
> >> For example, one execution of QEMU produced the following log:
> >>
> >> $ stap qemu-timing.stp
> >> 0.000 Start
> >> 0.036 Run
> >> 0.038 BIOS post
> >> 0.180 BIOS int 19
> >> 0.181 BIOS boot OS
> >> 0.181 LinuxBoot copy kernel
> >> 1.371 LinuxBoot copy initrd
> >
> > Yeah, there was a thread a bit ago about the performance of the interface to read the kernel/initrd. I think at it was using single byte access instructions and there were patches to use string accessors instead? I can't remember where that threaded ended up.
>
> IIRC we're already using string accessors, but are still slow. Richard had a nice patch cooked up to basically have the fw_cfg interface be able to DMA its data to the guest. I like the idea. Avi did not.
>
> And yes, bad -kernel performance does hurt in some workloads. A lot.
>
>
The rep/ins implementation is still slow, optimizing it can help.
What does 'perf top' say when running this workload?
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2011-10-11 9:08 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
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 ` Avi Kivity [this message]
2011-10-11 9:18 ` [Qemu-devel] " Daniel P. Berrange
2011-10-11 9:35 ` Avi Kivity
2011-10-10 23:57 ` Kevin O'Connor
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