On Thu, Mar 28, 2024 at 03:02:30AM +0000, Liu, Yuan1 wrote: > Yes, I will support software fallback to ensure CI testing and users can > still use qpl compression without IAA hardware. > > Although the qpl software solution will have better performance than zlib, > I still don't think it has a greater advantage than zstd. I don't think there > is a need to add a migration option to configure the qpl software or hardware > path. > So I will still only use QPL as an independent compression in the next > version, and > no other migration options are needed.
That should be fine. > > I will also add a guide to qpl-compression.rst about IAA permission issues > and how to > determine whether the hardware path is available. OK. [...] > > > Yes, I use iperf3 to check the bandwidth for one core, the bandwith is > > 60Gbps. > > > [ ID] Interval Transfer Bitrate Retr Cwnd > > > [ 5] 0.00-1.00 sec 7.00 GBytes 60.1 Gbits/sec 0 2.87 MBytes > > > [ 5] 1.00-2.00 sec 7.05 GBytes 60.6 Gbits/sec 0 2.87 Mbytes > > > > > > And in the live migration test, a multifd thread's CPU utilization is > > almost 100% > > > > This 60Gpbs per-channel is definitely impressive.. > > > > Have you tried migration without multifd on your system? Would that also > > perform similarly v.s. 2 channels multifd? > > Simple Test result below: > VM Type: 16vCPU, 64G memory > Workload in VM: fill 56G memory with Silesia data and vCPUs are idle > Migration Configurations: > 1. migrate_set_parameter max-bandwidth 100G > 2. migrate_set_parameter downtime-limit 300 > 3. migrate_set_capability multifd on (multiFD test case) > 4. migrate_set_parameter multifd-channels 2 (multiFD test case) > > Totaltime (ms) Downtime (ms) Throughput (mbps) > Pages-per-second > without Multifd 23580 307 21221 689588 > Multifd 2 7657 198 65410 2221176 Thanks for the test results. So I am guessing the migration overheads besides pushing the socket is high enough to make it drop drastically, even if in this case zero detection shouldn't play a major role considering most of guest mem is pre-filled. -- Peter Xu
