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? It was run on ramfs, since that's the only thing that transparent huge page cache supports right now? > ** 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? > 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. -- 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>