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: 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' 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.

At 2017-04-26 19:26:53, "Chao Fan" <fanc.fnst(a)cn.fujitsu.com&gt; 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?

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 &gt;libvir-list(a)redhat.com >https://www.redhat.com/mailman/listinfo/libvir-list