Dave Hansen wrote: > On 04/15/2013 11:17 AM, Kirill A. Shutemov wrote: > > I run iozone using mmap files (-B) with different number of threads. > > The test machine is 4s Westmere - 4x10 cores + HT. > > How did you run this, exactly? Which iozone arguments? iozone -B -s 21822226/$threads -t $threads -r 4 -i 0 -i 1 -i 2 -i 3 It's slightly modified iozone test from mmtests. > It was run on ramfs, since that's the only thing that transparent huge page > cache supports right now? Correct. > > ** Initial writers ** > > threads: 1 2 4 8 16 32 64 128 256 > > baseline: 1103360 912585 500065 260503 128918 62039 34799 18718 9376 > > patched: 2127476 2155029 2345079 1942158 1127109 571899 127090 52939 25950 > > speed-up(times): 1.93 2.36 4.69 7.46 8.74 9.22 3.65 2.83 2.77 > > I'm a _bit_ surprised that iozone scales _that_ badly especially while > threads<nr_cpus. Is this normal for iozone? What are the units and > metric there, btw? The units is KB/sec per process (I used 'Avg throughput per process' from iozone report). So it scales not that badly. I will use total children throughput next time to avoid confusion. > > Minimal speed up is in 1-thread reverse readers - 23%. > > Maximal is 9.2 times in 32-thread initial writers. It's probably due > > batched radix tree insert - we insert 512 pages a time. It reduces > > mapping->tree_lock contention. > > It might actually be interesting to see this at 10, 20, 40, 80, etc... > since that'll actually match iozone threads to CPU cores on your > particular system. Okay. -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>