On 09/27/2012 12:28 PM, Andrew Jones wrote: >> No, I am not there yet. >> >> So In summary, we are suffering with inconsistent benchmark result, >> while measuring the benefit of our improvement in PLE/pvlock etc.. > > Are you measuring the combined throughput of all running guests, or > just looking at the results of the benchmarks in a single test guest? > > I've done some benchmarking as well and my stddevs look pretty good for > kcbench, ebizzy, dbench, and sysbench-memory. I do 5 runs for each > overcommit level (1.0 - 3.0, stepped by .25 or .5), and 2 runs of that > full sequence of tests (one with the overcommit levels in scrambled > order). The relative stddevs for each of the sets of 5 runs look pretty > good, and the data for the 2 runs match nicely as well. > > To try and get consistent results I do the following > - interleave the memory of all guests across all numa nodes on the > machine > - echo 0 > /proc/sys/kernel/randomize_va_space on both host and test > guest > - echo 3 > /proc/sys/vm/drop_caches on both host and test guest before > each run > - use a ramdisk for the benchmark output files on all running guests > - no periodically running services installed on the test guest > - HT is turned off as you do, although I'd like to try running again > with it turned back on > > Although, I still need to run again measuring the combined throughput > of all running vms (including the ones launched just to generate busy > vcpus). Maybe my results won't be as consistent then... > Another way to test is to execute perf stat -e 'kvm_exit exit_reason==40' sleep 10 to see how many PAUSEs were intercepted in a given time (except I just invented the filter syntax). The fewer we get, the more useful work the system does. This ignores kvm_vcpu_on_spin overhead though, so it's just a rough measure. -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
