From: Paolo Bonzini <pbonzini@redhat.com>
To: Ming Lei <ming.lei@canonical.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Peter Maydell <peter.maydell@linaro.org>,
Fam Zheng <famz@redhat.com>,
"Michael S. Tsirkin" <mst@redhat.com>,
qemu-devel <qemu-devel@nongnu.org>,
Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 01/15] qemu coroutine: support bypass mode
Date: Thu, 31 Jul 2014 11:15:44 +0200 [thread overview]
Message-ID: <53DA0940.2030207@redhat.com> (raw)
In-Reply-To: <CACVXFVMniMoquw-BQ86VZKPT-1n6p6gp7m01MtioZf=+BugidQ@mail.gmail.com>
Il 31/07/2014 10:59, Ming Lei ha scritto:
>> > No guesses please. Actually that's also my guess, but since you are
>> > submitting the patch you must do better and show profiles where stack
>> > switching disappears after the patches.
> Follows the below hardware events reported by 'perf stat' when running
> fio randread benchmark for 2min in VM(single vq, 2 jobs):
>
> sudo ~/bin/perf stat -e
> L1-dcache-loads,L1-dcache-load-misses,cpu-cycles,instructions,branch-instructions,branch-misses,branch-loads,branch-load-misses,dTLB-loads,dTLB-load-misses
> ./nqemu-start-mq 4 1
>
> 1), without bypassing coroutine via forcing to set 's->raw_format ' as
> false, see patch 5/15
>
> - throughout: 95K
> 232,564,905,115 instructions
> 161.991075781 seconds time elapsed
>
>
> 2), with bypassing coroutinue
> - throughput: 115K
> 255,526,629,881 instructions
> 162.333465490 seconds time elapsed
Ok, so you are saving 10% instructions per iop: before 232G / 95K =
2.45M instructions/iop, 255G / 115K = 2.22M instructions/iop.
That's not small, and it's a good thing for CPU utilization even if you
were not increasing iops. On top of this, can you provide the stack
traces to see the difference in the profiles?
Paolo
next prev parent reply other threads:[~2014-07-31 9:16 UTC|newest]
Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-30 11:39 [Qemu-devel] [PATCH 00/14] dataplane: optimization and multi virtqueue support Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 01/15] qemu coroutine: support bypass mode Ming Lei
2014-07-30 13:45 ` Paolo Bonzini
2014-07-30 17:15 ` Ming Lei
2014-07-30 23:37 ` Paolo Bonzini
2014-07-31 3:55 ` Ming Lei
2014-07-31 7:37 ` Benoît Canet
2014-07-31 9:47 ` Ming Lei
2014-07-31 10:45 ` Paolo Bonzini
2014-08-01 13:38 ` Ming Lei
2014-07-31 8:59 ` Ming Lei
2014-07-31 9:15 ` Paolo Bonzini [this message]
2014-07-31 10:06 ` Ming Lei
2014-07-31 16:13 ` Ming Lei
2014-07-31 16:30 ` Paolo Bonzini
2014-08-01 2:54 ` Ming Lei
2014-08-01 13:13 ` Stefan Hajnoczi
2014-08-01 13:48 ` Ming Lei
2014-08-01 14:17 ` Paolo Bonzini
2014-08-01 15:21 ` Ming Lei
2014-08-01 14:52 ` Ming Lei
2014-08-01 16:03 ` Stefan Hajnoczi
2014-08-02 2:42 ` Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 02/15] qemu aio: prepare for supporting selective bypass coroutine Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 03/15] block: support to bypass qemu coroutinue Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 04/15] Revert "raw-posix: drop raw_get_aio_fd() since it is no longer used" Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 05/15] dataplane: enable selective bypassing coroutine Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 06/15] qemu/obj_pool.h: introduce object allocation pool Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 07/15] dataplane: use object pool to speed up allocation for virtio blk request Ming Lei
2014-07-30 14:14 ` Paolo Bonzini
2014-07-30 15:09 ` Michael S. Tsirkin
2014-07-31 3:22 ` Ming Lei
2014-07-31 9:18 ` Paolo Bonzini
2014-08-01 7:42 ` Ming Lei
2014-08-04 10:21 ` Stefan Hajnoczi
2014-08-04 11:42 ` Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 08/15] virtio: decrease size of VirtQueueElement Ming Lei
2014-07-30 13:51 ` Paolo Bonzini
2014-07-30 14:40 ` Michael S. Tsirkin
2014-07-30 14:50 ` Paolo Bonzini
2014-07-31 2:11 ` Ming Lei
2014-07-31 2:07 ` Ming Lei
2014-07-31 9:38 ` Paolo Bonzini
2014-08-01 3:34 ` Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 09/15] linux-aio: fix submit aio as a batch Ming Lei
2014-07-30 13:59 ` Paolo Bonzini
2014-07-30 17:32 ` Ming Lei
2014-07-30 23:41 ` Paolo Bonzini
2014-07-30 11:39 ` [Qemu-devel] [PATCH 10/15] linux-aio: increase max event to 256 Ming Lei
2014-07-30 12:15 ` Eric Blake
2014-07-30 14:00 ` Paolo Bonzini
2014-07-30 17:20 ` Ming Lei
2014-08-04 10:26 ` Stefan Hajnoczi
2014-07-30 11:39 ` [Qemu-devel] [PATCH 11/15] linux-aio: remove 'node' from 'struct qemu_laiocb' Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 12/15] hw/virtio-pci: introduce num_queues property Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 13/15] hw/virtio/virtio-blk.h: introduce VIRTIO_BLK_F_MQ Ming Lei
2014-07-30 11:39 ` [Qemu-devel] [PATCH 14/15] hw/block/virtio-blk: create num_queues vqs if dataplane is enabled Ming Lei
2014-07-30 14:01 ` Paolo Bonzini
2014-07-30 15:12 ` Michael S. Tsirkin
2014-07-30 15:25 ` Paolo Bonzini
2014-07-31 3:47 ` Ming Lei
2014-07-31 8:52 ` Paolo Bonzini
2014-08-01 3:09 ` Ming Lei
2014-08-01 3:24 ` Ming Lei
2014-08-01 6:10 ` Paolo Bonzini
2014-08-01 7:35 ` Ming Lei
2014-08-01 7:46 ` Paolo Bonzini
2014-07-30 11:39 ` [Qemu-devel] [PATCH 15/15] dataplane: virtio-blk: support mutlti virtqueue Ming Lei
2014-07-30 12:42 ` [Qemu-devel] [PATCH 00/14] dataplane: optimization and multi virtqueue support Christian Borntraeger
2014-08-04 10:16 ` Stefan Hajnoczi
2014-08-04 10:45 ` Ming Lei
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