[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH v2 0/3] io-thread optimizations
From: |
Jan Kiszka |
Subject: |
Re: [Qemu-devel] [PATCH v2 0/3] io-thread optimizations |
Date: |
Tue, 26 Apr 2011 09:36:30 +0200 |
User-agent: |
Mozilla/5.0 (X11; U; Linux i686 (x86_64); de; rv:1.8.1.12) Gecko/20080226 SUSE/2.0.0.12-1.1 Thunderbird/2.0.0.12 Mnenhy/0.7.5.666 |
On 2011-04-25 20:35, Aurelien Jarno wrote:
> On Thu, Apr 14, 2011 at 09:14:35AM +0200, Jan Kiszka wrote:
>> On 2011-04-13 22:16, Aurelien Jarno wrote:
>>> On Mon, Apr 11, 2011 at 10:27:41PM +0200, Jan Kiszka wrote:
>>>> These patches were posted before. They bring down the overhead of the
>>>> io-thread mode for TCG here, specifically when emulating SMP.
>>>>
>>>> The major change in this version, besides rebasing, is the exclusion of
>>>> KVM from the main loop polling optimization.
>>>>
>>>>
>>>>
>>>> Jan Kiszka (3):
>>>> Do not drop global mutex for polled main loop runs
>>>> Poll main loop after I/O events were received
>>>> Do not kick vcpus in TCG mode
>>>>
>>>> cpus.c | 2 +-
>>>> sysemu.h | 2 +-
>>>> vl.c | 22 ++++++++++++++++------
>>>> 3 files changed, 18 insertions(+), 8 deletions(-)
>>>>
>>>
>>> Thanks for working on improving the io-thread with TCG. Your patches
>>> make sense, but they don't seems to fix the slowdown observed when
>>> enabling the io-thread. Well maybe they were not supposed to. This is
>>> for example the results of netperf between guest and host using virtio:
>>>
>>> no io-thread 122 MB/s
>>> io-thread 97 MB/s
>>> io-thread + patches 98 MB/s
>>>
>>
>> Can you capture ftraces of io-thread enabled & disabled runs? They just
>> need to cover a hand full of frames.
>>
>
> From what I have been able to get from the ftraces documentation, it's
> possible multiple tracers. Which tracers would you like to use there?
> The best would be a set of command lines to run.
Sorry, of course: Just download, build & install trace-cmd [1], then
execute "trace-cmd record -b 16000 -e all" while qemu is running. The
result is written to trace.dat in the current directory. Visualize it
via "trace-cmd report" (or kernelshark if you built that as well).
Jan
[1] git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
signature.asc
Description: OpenPGP digital signature
- [Qemu-devel] [PATCH v2 3/3] Do not kick vcpus in TCG mode, (continued)
- [Qemu-devel] [PATCH v2 3/3] Do not kick vcpus in TCG mode, Jan Kiszka, 2011/04/11
- [Qemu-devel] [PATCH v2 2/3] Poll main loop after I/O events were received, Jan Kiszka, 2011/04/11
- [Qemu-devel] [PATCH v2 1/3] Do not drop global mutex for polled main loop runs, Jan Kiszka, 2011/04/11
- Re: [Qemu-devel] [PATCH v2 0/3] io-thread optimizations, Paolo Bonzini, 2011/04/12
- Re: [Qemu-devel] [PATCH v2 0/3] io-thread optimizations, Aurelien Jarno, 2011/04/13
- Re: [Qemu-devel] [PATCH v2 0/3] io-thread optimizations, Aurelien Jarno, 2011/04/25
- Re: [Qemu-devel] [PATCH v2 0/3] io-thread optimizations,
Jan Kiszka <=