On Tue, Nov 20, 2012 at 01:31:56PM +0100, Ingo Molnar wrote: > > * Ingo Molnar <mi...@kernel.org> wrote: > > > * Ingo Molnar <mi...@kernel.org> wrote: > > > > > numa/core profile: > > > > > > 95.66% perf-1201.map [.] 0x00007fe4ad1c8fc7 > > > 1.70% libjvm.so [.] 0x0000000000381581 > > > 0.59% [vdso] [.] 0x0000000000000607 > > > 0.19% [kernel] [k] do_raw_spin_lock > > > 0.11% [kernel] [k] generic_smp_call_function_interrupt > > > 0.11% [kernel] [k] timekeeping_get_ns.constprop.7 > > > 0.08% [kernel] [k] ktime_get > > > 0.06% [kernel] [k] get_cycles > > > 0.05% [kernel] [k] __native_flush_tlb > > > 0.05% [kernel] [k] rep_nop > > > 0.04% perf [.] add_hist_entry.isra.9 > > > 0.04% [kernel] [k] rcu_check_callbacks > > > 0.04% [kernel] [k] ktime_get_update_offsets > > > 0.04% libc-2.15.so [.] __strcmp_sse2 > > > > > > No page fault overhead (see the page fault rate further below) > > > - the NUMA scanning overhead shows up only through some mild > > > TLB flush activity (which I'll fix btw). > > > > The patch attached below should get rid of that mild TLB > > flushing activity as well. > > This has further increased SPECjbb from 203k/sec to 207k/sec, > i.e. it's now 5% faster than mainline - THP enabled. > > The profile is now totally flat even during a full 32-WH SPECjbb > run, with the highest overhead entries left all related to timer > IRQ processing or profiling. That is on a system that should be > very close to yours. >
This is a stab in the dark but are you always running with profiling enabled? I have not checked this with perf but a number of years ago I found that oprofile could distort results really badly (7-30% depending on the workload at the time) when I was evalating hugetlbfs and THP. In some cases I would find that profiling would show that a patch series improved performance when the same series showed regressions if profiling was disabled. The sampling rate had to be reduced quite a bit to avoid this effect. -- Mel Gorman SUSE Labs -- 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/
