Re: [PATCH v2 0/5] migration: improve multithreads

From: Xiao Guangrong <guangrong.xiao@gmail.com>
To: pbonzini@redhat.com, mst@redhat.com, mtosatti@redhat.com
Cc: kvm@vger.kernel.org, quintela@redhat.com,
	Xiao Guangrong <xiaoguangrong@tencent.com>,
	qemu-devel@nongnu.org, peterx@redhat.com, dgilbert@redhat.com,
	wei.w.wang@intel.com, cota@braap.org, jiang.biao2@zte.com.cn
Subject: Re: [PATCH v2 0/5] migration: improve multithreads
Date: Mon, 12 Nov 2018 11:07:59 +0800	[thread overview]
Message-ID: <2c351ac2-ad51-13de-6aea-ffc014edeffe@gmail.com> (raw)
In-Reply-To: <20181106122025.3487-1-xiaoguangrong@tencent.com>

Hi,

Ping...

On 11/6/18 8:20 PM, guangrong.xiao@gmail.com wrote:
> From: Xiao Guangrong <xiaoguangrong@tencent.com>
> 
> Changelog in v2:
> These changes are based on Paolo's suggestion:
> 1) rename the lockless multithreads model to threaded workqueue
> 2) hugely improve the internal design, that make all the request be
>     a large array, properly partition it, assign requests to threads
>     respectively and use bitmaps to sync up threads and the submitter,
>     after that ptr_ring and spinlock are dropped
> 3) introduce event wait for the submitter
> 
> These changes are based on Emilio's review:
> 4) make more detailed description for threaded workqueue
> 5) add a benchmark for threaded workqueue
> 
> The previous version can be found at
> 	https://marc.info/?l=kvm&m=153968821910007&w=2
> 
> There's the simple performance measurement comparing these two versions,
> the environment is the same as we listed in the previous version.
> 
> Use 8 threads to compress the data in the source QEMU
> - with compress-wait-thread = off
> 
> 
>        total time        busy-ratio
> --------------------------------------------------
> v1    125066            0.38
> v2    120444            0.35
> 
> - with compress-wait-thread = on
>           total time    busy-ratio
> --------------------------------------------------
> v1    164426            0
> v2    142609            0
> 
> The v2 win slightly.
> 
> Xiao Guangrong (5):
>    bitops: introduce change_bit_atomic
>    util: introduce threaded workqueue
>    migration: use threaded workqueue for compression
>    migration: use threaded workqueue for decompression
>    tests: add threaded-workqueue-bench
> 
>   include/qemu/bitops.h             |  13 +
>   include/qemu/threaded-workqueue.h |  94 +++++++
>   migration/ram.c                   | 538 ++++++++++++++------------------------
>   tests/Makefile.include            |   5 +-
>   tests/threaded-workqueue-bench.c  | 256 ++++++++++++++++++
>   util/Makefile.objs                |   1 +
>   util/threaded-workqueue.c         | 466 +++++++++++++++++++++++++++++++++
>   7 files changed, 1030 insertions(+), 343 deletions(-)
>   create mode 100644 include/qemu/threaded-workqueue.h
>   create mode 100644 tests/threaded-workqueue-bench.c
>   create mode 100644 util/threaded-workqueue.c
> 