Re: [Qemu-devel] [regression] dataplane: throughout -40% by commit 580b6b2aa2

[Ming Lei]

On Mon, Jun 30, 2014 at 4:08 PM, Stefan Hajnoczi <address@hidden> wrote:
>
> Try:
> $ perf record -e syscalls:* --tid <iothread-tid>
> ^C
> $ perf script # shows the trace log
>
> The difference between syscalls in QEMU 2.0 and qemu.git/master could
> reveal the problem.

The difference is that there are tons of write() and rt_sigprocmask()
in qemu.git/master, I guess it is related coroutinue.

For linux-aio, the coroutinue shouldn't be necessary because
io_submit() won't block at most of times for O_DIRECT read/write.


Thanks,
-- 
Ming Lei