Nick Piggin wrote:
OK, sure. I think we need more numbers though.
Thinking about the issue some more, I think I know just the number we might want to know. It is pretty obvious that the kernel needs to do less work with the MADV_FREE code present. However, it is possible that userspace needs to do more work, by accessing pages that are not in the CPU cache, or in another CPU's cache. In the test cases where you see similar performance on the workload with and without the MADV_FREE code, are you by any chance seeing lower system time and higher user time? I think that maybe for 2.6.22 we should just alias MADV_FREE to run with the MADV_DONTNEED functionality, so that the glibc people can make the change on their side while we figure out what will be the best thing to do on the kernel side. I'll send in a patch that does that once Linus has committed your most recent flood of patches. What do you think? -- Politics is the struggle between those who want to make their country the best in the world, and those who believe it already is. Each group calls the other unpatriotic. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
