Bill Gray wrote: > > See attachment with two graphs: (1) cache bandwidth, (2) blowup of > sustained memory bandwidth region... Bill, I had some difficulty with this document under ooffice. A recent version seized and an older version didn't seem to render correctly. Could you export it as pdf? Thanks, -john > - X axis has a log scale > > - Light blue line is an older system with 32K L1 and 6M L2 caches > > - All other measurements on perf34: 32K L1, 256K L2, 30M L3 caches > > - Majority of variation in L1 cache region is from the two guest > measurements done with no taskset to a VCPU: yellow and maroon lines. > Perhaps this reflects the test bouncing between VCPUs in the guest. > > - The sustained memory bandwidth for the guest with no pinning is only > 80% of native (maroon line), which motivates more convenient and > comprehensive numactl for guests. > > - Virtualized bandwidth is otherwise nearly in line with native, which > confirms the importance of the virtual CPUID communicating actual native > cache sizes to cache-size-aware guest applications, since guest apps > could benefit from the full size of the native cache. (Guest was > started with "-cpu host", but lscpu in guest showed 4M cache despite > actual 30M cache.) -- john.cooper@xxxxxxxxxx -- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list