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From: Xiao Guangrong <guangrong.xiao@gmail.com>
To: "Michael S. Tsirkin" <mst@redhat.com>, Jason Wang <jasowang@redhat.com>
Cc: pbonzini@redhat.com, mtosatti@redhat.com, qemu-devel@nongnu.org,
	kvm@vger.kernel.org, dgilbert@redhat.com, peterx@redhat.com,
	jiang.biao2@zte.com.cn, wei.w.wang@intel.com,
	Xiao Guangrong <xiaoguangrong@tencent.com>
Subject: Re: [Qemu-devel] [PATCH 09/12] ring: introduce lockless ring buffer
Date: Fri, 29 Jun 2018 15:44:25 +0800	[thread overview]
Message-ID: <c6066241-d693-57f3-96dd-c7300ce3818d@gmail.com> (raw)
In-Reply-To: <20180629072313-mutt-send-email-mst@kernel.org>



On 06/29/2018 12:23 PM, Michael S. Tsirkin wrote:
> On Thu, Jun 28, 2018 at 09:36:00PM +0800, Jason Wang wrote:
>>
>>
>> On 2018年06月04日 17:55, guangrong.xiao@gmail.com wrote:
>>> From: Xiao Guangrong<xiaoguangrong@tencent.com>
>>>

>>> Memory barrier is omitted here, please refer to the comment in the code.
>>>
>>> (1)https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/kfifo.h
>>> (2)http://dpdk.org/doc/api/rte__ring_8h.html
>>>
>>> Signed-off-by: Xiao Guangrong<xiaoguangrong@tencent.com>
>>> ---
>>
>> May I ask why you need a MPSC ring here? Can we just use N SPSC ring for
>> submitting pages and another N SPSC ring for passing back results?
>>
>> Thanks
> 
> Or just an SPSC ring + a lock.
> How big of a gain is lockless access to a trivial structure
> like the ring?
> 

Okay, i will give a try.

BTW, we tried to use a global ring + lock for input and lockless ring for input,
the former did not show better performance. But we haven't tried to use global
ring + lock for out yet.

  reply	other threads:[~2018-06-29  7:44 UTC|newest]

Thread overview: 78+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-04  9:55 [Qemu-devel] [PATCH 00/12] migration: improve multithreads for compression and decompression guangrong.xiao
2018-06-04  9:55 ` [Qemu-devel] [PATCH 01/12] migration: do not wait if no free thread guangrong.xiao
2018-06-11  7:39   ` Peter Xu
2018-06-12  2:42     ` Xiao Guangrong
2018-06-12  3:15       ` Peter Xu
2018-06-13 15:43         ` Dr. David Alan Gilbert
2018-06-14  3:19           ` Xiao Guangrong
2018-06-04  9:55 ` [Qemu-devel] [PATCH 02/12] migration: fix counting normal page for compression guangrong.xiao
2018-06-13 15:51   ` Dr. David Alan Gilbert
2018-06-14  3:32     ` Xiao Guangrong
2018-06-04  9:55 ` [Qemu-devel] [PATCH 03/12] migration: fix counting xbzrle cache_miss_rate guangrong.xiao
2018-06-13 16:09   ` Dr. David Alan Gilbert
2018-06-15 11:30   ` Dr. David Alan Gilbert
2018-06-04  9:55 ` [Qemu-devel] [PATCH 04/12] migration: introduce migration_update_rates guangrong.xiao
2018-06-13 16:17   ` Dr. David Alan Gilbert
2018-06-14  3:35     ` Xiao Guangrong
2018-06-15 11:32     ` Dr. David Alan Gilbert
2018-06-04  9:55 ` [Qemu-devel] [PATCH 05/12] migration: show the statistics of compression guangrong.xiao
2018-06-04 22:31   ` Eric Blake
2018-06-06 12:44     ` Xiao Guangrong
2018-06-13 16:25   ` Dr. David Alan Gilbert
2018-06-14  6:48     ` Xiao Guangrong
2018-07-16 19:01       ` Dr. David Alan Gilbert
2018-07-18  8:51         ` Xiao Guangrong
2018-06-04  9:55 ` [Qemu-devel] [PATCH 06/12] migration: do not detect zero page for compression guangrong.xiao
2018-06-19  7:30   ` Peter Xu
2018-06-28  9:12     ` Xiao Guangrong
2018-06-28  9:36       ` Daniel P. Berrangé
2018-06-29  3:50         ` Xiao Guangrong
2018-06-29  9:54         ` Dr. David Alan Gilbert
2018-06-29  9:42       ` Dr. David Alan Gilbert
2018-07-03  3:53         ` Xiao Guangrong
2018-07-16 18:58           ` Dr. David Alan Gilbert
2018-07-18  8:46             ` Xiao Guangrong
2018-07-22 16:05               ` Michael S. Tsirkin
2018-07-23  7:12                 ` Xiao Guangrong
2018-06-04  9:55 ` [Qemu-devel] [PATCH 07/12] migration: hold the lock only if it is really needed guangrong.xiao
2018-06-19  7:36   ` Peter Xu
2018-06-28  9:33     ` Xiao Guangrong
2018-06-29 11:22       ` Dr. David Alan Gilbert
2018-07-03  6:27         ` Xiao Guangrong
2018-07-11  8:21       ` Peter Xu
2018-07-12  7:47         ` Xiao Guangrong
2018-07-12  8:26           ` Peter Xu
2018-07-18  8:56             ` Xiao Guangrong
2018-07-18 10:18               ` Peter Xu
2018-07-13 17:44           ` Dr. David Alan Gilbert
2018-06-04  9:55 ` [Qemu-devel] [PATCH 08/12] migration: do not flush_compressed_data at the end of each iteration guangrong.xiao
2018-07-13 18:01   ` Dr. David Alan Gilbert
2018-07-18  8:44     ` Xiao Guangrong
2018-06-04  9:55 ` [Qemu-devel] [PATCH 09/12] ring: introduce lockless ring buffer guangrong.xiao
2018-06-20  4:52   ` Peter Xu
2018-06-28 10:02     ` Xiao Guangrong
2018-06-28 11:55       ` Wei Wang
2018-06-29  3:55         ` Xiao Guangrong
2018-07-03 15:55           ` Paul E. McKenney
2018-06-20  5:55   ` Peter Xu
2018-06-28 14:00     ` Xiao Guangrong
2018-06-20 12:38   ` Michael S. Tsirkin
2018-06-29  7:30     ` Xiao Guangrong
2018-06-29 13:08       ` Michael S. Tsirkin
2018-07-03  7:31         ` Xiao Guangrong
2018-06-28 13:36   ` Jason Wang
2018-06-29  3:59     ` Xiao Guangrong
2018-06-29  6:15       ` Jason Wang
2018-06-29  7:47         ` Xiao Guangrong
2018-06-29  4:23     ` Michael S. Tsirkin
2018-06-29  7:44       ` Xiao Guangrong [this message]
2018-06-04  9:55 ` [Qemu-devel] [PATCH 10/12] migration: introduce lockless multithreads model guangrong.xiao
2018-06-20  6:52   ` Peter Xu
2018-06-28 14:25     ` Xiao Guangrong
2018-07-13 16:24     ` Dr. David Alan Gilbert
2018-07-18  7:12       ` Xiao Guangrong
2018-06-04  9:55 ` [Qemu-devel] [PATCH 11/12] migration: use lockless Multithread model for compression guangrong.xiao
2018-06-04  9:55 ` [Qemu-devel] [PATCH 12/12] migration: use lockless Multithread model for decompression guangrong.xiao
2018-06-11  8:00 ` [Qemu-devel] [PATCH 00/12] migration: improve multithreads for compression and decompression Peter Xu
2018-06-12  3:19   ` Xiao Guangrong
2018-06-12  5:36     ` Peter Xu

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