Re: numa/core regressions fixed - more testers wanted

From: David Rientjes
Date: Tue Nov 20 2012 - 22:33:09 EST


On Tue, 20 Nov 2012, Ingo Molnar wrote:

> The current updated table of performance results is:
>
> -------------------------------------------------------------------------
> [ seconds ] v3.7 AutoNUMA | numa/core-v16 [ vs. v3.7]
> [ lower is better ] ----- -------- | ------------- -----------
> |
> numa01 340.3 192.3 | 139.4 +144.1%
> numa01_THREAD_ALLOC 425.1 135.1 | 121.1 +251.0%
> numa02 56.1 25.3 | 17.5 +220.5%
> |
> [ SPECjbb transactions/sec ] |
> [ higher is better ] |
> |
> SPECjbb 1x32 +THP 524k 507k | 638k +21.7%
> SPECjbb 1x32 !THP 395k | 512k +29.6%
> |
> -----------------------------------------------------------------------
> |
> [ SPECjbb multi-4x8 ] |
> [ tx/sec ] v3.7 | numa/core-v16
> [ higher is better ] ----- | -------------
> |
> +THP: 639k | 655k +2.5%
> -THP: 510k | 517k +1.3%
>
> So I think I've addressed all regressions reported so far - if
> anyone can still see something odd, please let me know so I can
> reproduce and fix it ASAP.
>

I started profiling on a new machine that is an exact duplicate of the
16-way, 4 node, 32GB machine I was profiling with earlier to rule out any
machine-specific problems. I pulled master and ran new comparisons with
THP enabled at c418de93e398 ("Merge branch 'x86/mm'"):

CONFIG_NUMA_BALANCING disabled 136521.55 SPECjbb2005 bops
CONFIG_NUMA_BALANCING enabled 132476.07 SPECjbb2005 bops (-3.0%)

Aside: neither 4739578c3ab3 ("x86/mm: Don't flush the TLB on #WP pmd
fixups") nor 01e9c2441eee ("x86/vsyscall: Add Kconfig option to use native
vsyscalls and switch to it") significantly improved upon the throughput on
this system.

Over the past 24 hours, however, throughput has significantly improved
from a 6.3% regression to a 3.0% regression because of 246c0b9a1caf ("mm,
numa: Turn 4K pte NUMA faults into effective hugepage ones")!

One request: I noticed that the entire patchset doesn't add any fields to
/proc/vmstat through count_vm_event() like thp did, which I found very
useful when profiling that set when it was being reviewed. Would it be
possible to add some vm events to the balancing code so we can capture
data of how the NUMA balancing is behaving? Their usefulness would extend
beyond just the review period.
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