On Tue, Sep 02, 2014 at 05:20:55PM -0700, Linus Torvalds wrote: > On Tue, Sep 2, 2014 at 5:10 PM, Johannes Weiner <han...@cmpxchg.org> wrote: > > > > That looks like a partial profile, where did the page allocator, page > > zeroing etc. go? Because the distribution among these listed symbols > > doesn't seem all that crazy: > > Please argue this *after* the commit has been reverted. You guys can > try to make the memcontrol batching actually work and scale later. > It's not appropriate to argue against major regressions when reported > and bisected by users.
I'll send a clean revert later. > Showing the spinlock at the top of the profile is very much crazy > (apparently taking 68% of all cpu time), when it's all useless > make-believe work. I don't understand why you wouldn't call that > crazy. If you limit perf to a subset of symbols, it will show a relative distribution between them, i.e: perf top --symbols kfree,memset during some disk access: PerfTop: 1292 irqs/sec kernel:84.4% exact: 0.0% [4000Hz cycles], (all, 4 CPUs) ------------------------------------------------------------------------------- 56.23% [kernel] [k] kfree 41.86% [kernel] [k] memset 1.91% libc-2.19.so [.] memset kfree isn't eating 56% of "all cpu time" here, and it wasn't clear to me whether Dave filtered symbols from only memcontrol.o, memory.o, and mmap.o in a similar way. I'm not arguing against the regression, I'm just trying to make sense of the numbers from the *patched* kernel. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/