On Thu, Apr 27, 2017 at 02:24:25PM +0800, Chen Hanxiao wrote: > > >At 2017-04-26 19:26:53, "Chao Fan" <fanc.fnst@xxxxxxxxxxxxxx> wrote: >>Hi all, >> >>When migrating a guest which consumes too much CPU & memory, dirty >>pages amount will increase significantly, so does the migration >>time, migration can not even complete, at worst. >> >>So I made an RFC patch in QEMU to set cpu throttle value by workload >>when migration. The test result and the RFC patch are here: >>https://lists.gnu.org/archive/html/qemu-devel/2017-01/msg03479.html >> >>But this idea was not accepted by QEMU community. So I want to do a >>similar feature in libvirt: > >Hi, Fan >> >>Step 1: Add --auto-converge-smart parameter to migrate. >>Step 2: Add a timer in qemu-driver to get the 'info migrate' to check >> if the dirty-pages-rate updated every 1 second or 0.5 second >> when migration. >>Step 3: If updated, change the cpu throttle value according to the >> dirty-pages-rate and page-size by >> 'migrate_set_parameter cpu-throttle-increment' > >If dirty-pages-rate rising, we increase cpu-throttle-increment; >if it falling after a while, >would we decrease cpu-throttle-increment then? Hi Chen, Yes, that's what I want to do. The cpu throttle value is larger, the migration will be faster. On the other hand, the performance loss of the guest will be worse. It's a ballance problem. If dirty-pages-rate gets small, it proves the cpu throttle is suitable. So I think it's better to decrease cpu-throttle-increment to avoid more performance loss. Thanks, Chao Fan > >Regards, >- Chen > >> >>I think this feature makes auto-converge smarter than leaving the >>cpu throttle value with default 20/10 or set by users. >>And also it can save time. >> >>Any comments will be welcome. > > > > >> >>Thanks, >>Chao Fan >> >> >> >>-- >>libvir-list mailing list >>libvir-list@xxxxxxxxxx >>https://www.redhat.com/mailman/listinfo/libvir-list > > -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list
