> -----Original Message----- > From: Derek Su <jwsu1...@gmail.com> > Sent: Thursday, April 9, 2020 3:11 PM > To: Zhang, Chen <chen.zh...@intel.com> > Cc: Lukas Straub <lukasstra...@web.de>; Derek Su <dere...@qnap.com>; > qemu-devel@nongnu.org; lizhij...@cn.fujitsu.com; chy...@qnap.com; > jasow...@redhat.com; ctch...@qnap.com > Subject: Re: [PATCH v4 2/2] net/colo-compare.c: handling of the full primary > or secondary queue > > Hello, Zhang and Lukas > > Sure, after my re-test, the performance is hurt. Will update it later. > > By the way, could I also move the "error_report("colo compare > primary/secondary queue size too big, drop packet");" to trace?
Yes. > The use of error_report is a little strange and make a flood in log. > > May I also make "MAX_QUEUE_SIZE" be user-configurable in this series? I have this patch internal and will send it later. Thanks Zhang Chen > > Thanks, > Derek Su > > > > > Zhang, Chen <chen.zh...@intel.com> 於 2020年4月9日 週四 下午2:59 > 寫道: > > > > > > > > > -----Original Message----- > > > From: Lukas Straub <lukasstra...@web.de> > > > Sent: Thursday, April 9, 2020 3:19 AM > > > To: Derek Su <dere...@qnap.com> > > > Cc: qemu-devel@nongnu.org; lizhij...@cn.fujitsu.com; > > > chy...@qnap.com; jasow...@redhat.com; ctch...@qnap.com; Zhang, > Chen > > > <chen.zh...@intel.com>; jwsu1...@gmail.com > > > Subject: Re: [PATCH v4 2/2] net/colo-compare.c: handling of the full > > > primary or secondary queue > > > > > > On Sat, 28 Mar 2020 20:46:46 +0800 > > > Derek Su <dere...@qnap.com> wrote: > > > > > > > The pervious handling of the full primary or queue is only > > > > dropping the packet. If there are lots of clients to the guest VM, the > "drop" > > > > will lead to the lost of the networking connection until next > > > > checkpoint. > > > > > > > > To address the issue, this patch drops the packet firstly. > > > > Then, do checkpoint and flush packets. > > > > > > > > Signed-off-by: Derek Su <dere...@qnap.com> > > > > > > Hello, > > > I had a look at this again and did some benchmarking. > > > First just qemu 5.0-rc1 with my bugfixes ( > > > https://lists.nongnu.org/archive/html/qemu-devel/2020- > > > 04/msg01432.html ) Then qemu 5.0-rc1 with my bugfixes and this patch > > > series. > > > > > > This commit hurts performance too much: > > > Client-to-server bandwidth falls from ~45.9 Mbit/s to 22.9 Mbit/s. > > > Server-to-client bandwidth falls from ~6.3 Mbit/s to just ~674 Kbit/s. > > > Average latency rises from ~197ms to ~397ms. > > > > > > Meanwhile the packet loss without this commit is negligible, only > > > 1-2 ping packets got lost during each test run. > > > > > > Instead I think we should just turn the error message into a trace > > > so it doesn't flood the logs. > > > > We re-test this patch, Lukas is right. > > Sorry for the original idea, looks like it did not show better performance > > in > the test. > > Agree with Lukas's comments. Derek, can you please change it? > > > > Thanks > > Zhang Chen > > > > > > > > > > Regards, > > > Lukas Straub