Date: Fri, 03 Feb 2017 19:49:53 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 216759] [qemu] Memory speed significantly slower under QEMUKVM emulation according to sysbench Message-ID: <bug-216759-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D216759 Bug ID: 216759 Summary: [qemu] Memory speed significantly slower under QEMUKVM emulation according to sysbench Product: Base System Version: 11.0-RELEASE Hardware: Any OS: Any Status: New Severity: Affects Some People Priority: --- Component: kern Assignee: freebsd-bugs@FreeBSD.org Reporter: andrew@azar-a.net FreeBSD 11-RELEASE and 10.3-RELEASE seem to run memory much slower accordin= g to sysbench benchmarking software: Bare Metal run: # uname -a FreeBSD backup 10.3-RELEASE-p11 FreeBSD 10.3-RELEASE-p11 #0: Mon Oct 24 18:49:24 UTC 2016=20=20=20=20 root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC amd64 # sysbench --num-threads=3D1 --test=3Dmemory --memory-total-size=3D1G run sysbench 0.4.12: multi-threaded system evaluation benchmark Running the test with following options: Number of threads: 1 Doing memory operations speed test Memory block size: 1K Memory transfer size: 1024M Memory operations type: write Memory scope type: global Threads started! Done. Operations performed: 1048576 (2183178.34 ops/sec) 1024.00 MB transferred (2132.01 MB/sec) Test execution summary: total time: 0.4803s total number of events: 1048576 total time taken by event execution: 0.3527 per-request statistics: min: 0.00ms avg: 0.00ms max: 7.56ms approx. 95 percentile: 0.00ms Threads fairness: events (avg/stddev): 1048576.0000/0.00 execution time (avg/stddev): 0.3527/0.00 QEMU KVM emulation: # uname -a FreeBSD dev 11.0-RELEASE-p2 FreeBSD 11.0-RELEASE-p2 #0: Mon Oct 24 06:55:27= UTC 2016 root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC a= md64 # sysbench --num-threads=3D1 --test=3Dmemory --memory-total-size=3D1G run sysbench 0.4.12: multi-threaded system evaluation benchmark Running the test with following options: Number of threads: 1 Doing memory operations speed test Memory block size: 1K Memory transfer size: 1024M Memory operations type: write Memory scope type: global Threads started! Done. Operations performed: 1048576 (69497.13 ops/sec) 1024.00 MB transferred (67.87 MB/sec) Test execution summary: total time: 15.0880s total number of events: 1048576 total time taken by event execution: 11.1440 per-request statistics: min: 0.01ms avg: 0.01ms max: 7.32ms approx. 95 percentile: 0.00ms Threads fairness: events (avg/stddev): 1048576.0000/0.00 execution time (avg/stddev): 11.1440/0.00 For comparison VMWARE: # uname -a FreeBSD ns3 10.2-RELEASE-p7 FreeBSD 10.2-RELEASE-p7 #0: Mon Nov 2 14:19:39= UTC 2015 root@amd64-builder.daemonology.net:/usr/obj/usr/src/sys/GENERIC a= md64 # sysbench --num-threads=3D1 --test=3Dmemory --memory-total-size=3D1G run sysbench 0.4.12: multi-threaded system evaluation benchmark Running the test with following options: Number of threads: 1 Doing memory operations speed test Memory block size: 1K Memory transfer size: 1024M Memory operations type: write Memory scope type: global Threads started! Done. Operations performed: 1048576 (2234641.77 ops/sec) 1024.00 MB transferred (2182.27 MB/sec) Test execution summary: total time: 0.4692s total number of events: 1048576 total time taken by event execution: 0.3437 per-request statistics: min: 0.00ms avg: 0.00ms max: 0.09ms approx. 95 percentile: 0.00ms Threads fairness: events (avg/stddev): 1048576.0000/0.00 execution time (avg/stddev): 0.3437/0.00 This is not 11 only problem. VPSs with 10.3 tested also have the same probl= em. I haven't found any info on this on the net. Might be because nobody tests = the RAM. Sysbench itself starts up a thread and runs the allocation code. I couldn't trace the thread though. Maybe it is old code of sysbench. Additional information and reports: https://www.reddit.com/r/freebsd/comments/5rtf05/abysmal_memory_perfomance_= witch_freebsd_under/ --=20 You are receiving this mail because: You are the assignee for the bug.=
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