From: John H. <ha...@en...> - 2001-03-15 02:20:23
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One correspondent wondered how representative the AIM7 workload is, fearing that my discovery of the awful scaling without that "pagecache_lock patch" might be peculiar to a non-Real World system workload. So I performed another set of tests of the 2.4.2 kernel vs. 2.4.2+"pagecache_lock patch". This time I did the classic kernel make, using -jN to parallelize as much as possible. Specifically: make ARCH=mips -j<N> MAKE="make ARCH=mips -j<N>" (That should do it, right?) The 2.4.2+pagecache_lock kernel is 19% faster than the baseline 2.4.2 kernel for -j4, and 37% faster for -j8. By comparison, with AIM7 at 8p the 2.4.2+pagecache_lock kernel is 63% faster. Okay, 37% isn't 63%, but the kernel 'make' runs with some idle time and it's a different workload than AIM7. The point still remains: the "pagecache_lock patch" is a significant improvement to scaling above 4p. For some reason, the kernel make misbehaves above -j8. It's as though 'make' believes I've asked for something like -j500. Hundreds of processes appear on the runqueue and the system grinds. Otherwise, I would have liked to do -j16 and -j32, which I believe would have demonstrated significantly better scaling for the "pagecache_lock patch" kernel. John Hawkes ha...@en... |