Hello Peter, On Tue, Aug 31, 2021 at 6:24 PM Peter Xu <pet...@redhat.com> wrote: > > On Tue, Aug 31, 2021 at 08:02:36AM -0300, Leonardo Bras wrote: > > Results: > > So far, the resource usage of __sys_sendmsg() reduced 15 times, and the > > overall migration took 13-18% less time, based in synthetic workload. > > Leo, > > Could you share some of the details of your tests? E.g., what's the > configuration of your VM for testing? What's the migration time before/after > the patchset applied? What is the network you're using? > > Thanks, > > -- > Peter Xu >
Sure, - Both receiving and sending hosts have 128GB ram and a 10Gbps network interface - There is a direct connection between the network interfaces. - The guest has 100GB ram, mem-lock=on and enable-kvm. - Before sending, I use a simple application to completely fill all guest pages with unique values, to avoid duplicated pages and zeroed pages. On a single test: Without zerocopy (qemu/master) - Migration took 123355ms, with an average of 6912.58 Mbps With Zerocopy: - Migration took 108514ms, with an average of 7858.39 Mbps This represents a throughput improvement around 13.6%. Comparing perf recorded during default and zerocopy migration: Without zerocopy: - copy_user_generic_string() uses 5.4% of cpu time - __sys_sendmsg() uses 5.19% of cpu time With zerocopy: - copy_user_generic_string() uses 0.02% of cpu time (~1/270 of the original) - __sys_sendmsg() uses 0.34% of cpu time (~1/15 of the original)
