On 11 August 2016 at 17:43, G 3 <programmingk...@gmail.com> wrote: > > On Aug 11, 2016, at 11:24 AM, qemu-devel-requ...@nongnu.org wrote: > > > Performance > > =========== > > > You can't do full work-load testing on this tree due to the lack of > > atomic support (but I will run some numbers on > > mttcg/base-patches-v4-with-cmpxchg-atomics-v2). However you certainly > > see a run time improvement with the kvm-unit-tests TCG group. > > > retry.py called with ['./run_tests.sh', '-t', '-g', 'tcg', '-o', '-accel > tcg,thread=single'] > > run 1: ret=0 (PASS), time=1047.147924 (1/1) > > run 2: ret=0 (PASS), time=1071.921204 (2/2) > > run 3: ret=0 (PASS), time=1048.141600 (3/3) > > Results summary: > > 0: 3 times (100.00%), avg time 1055.737 (196.70 varience/14.02 deviation) > > Ran command 3 times, 3 passes > > retry.py called with ['./run_tests.sh', '-t', '-g', 'tcg', '-o', '-accel > tcg,thread=multi'] > > run 1: ret=0 (PASS), time=303.074210 (1/1) > > run 2: ret=0 (PASS), time=304.574991 (2/2) > > run 3: ret=0 (PASS), time=303.327408 (3/3) > > Results summary: > > 0: 3 times (100.00%), avg time 303.659 (0.65 varience/0.80 deviation) > > Ran command 3 times, 3 passes > > > The TCG tests run with -smp 4 on my system. While the TCG tests are > > purely CPU bound they do exercise the hot and cold paths of TCG > > execution (especially when triggering SMC detection). However there is > > still a benefit even with a 50% overhead compared to the ideal 263 > > second elapsed time. > > > Alex > > > > Your tests results look very promising. It looks like you saw a 3x speed > improvement over single threading. Excellent. I wonder what the numbers > would be for a 22 core Xeon or 72 core Xeon Phi...
Well the initial results look like they tail off but I need to test on a more capable machine. I'm going to package up the test case first so people can easily replicate the test. > Do you think you could some test with an x86 guest like Windows XP? There > are plenty of benchmark tests for this platform. Video encoding, Youtube > video playback, and number crunching programs' results would be very > interesting to see. I don't have any Windows images to hand I'm afraid. Besides Windows is a fairly boring guest from this point of view because: - it's x86, so why use TCG over KVM - QEMU TCG generally sucks at media bencmarks due to SIMD emulation -- Alex Bennée KVM/QEMU Hacker for Linaro
