Messages in this thread | | | Date | Wed, 30 Jul 2008 10:34:07 -0700 | From | Andrew Morton <> | Subject | Re: [RFC] [PATCH 0/5 V2] Huge page backed user-space stacks |
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On Wed, 30 Jul 2008 18:23:18 +0100 Mel Gorman <mel@csn.ul.ie> wrote:
> On (30/07/08 01:43), Andrew Morton didst pronounce: > > On Mon, 28 Jul 2008 12:17:10 -0700 Eric Munson <ebmunson@us.ibm.com> wrote: > > > > > Certain workloads benefit if their data or text segments are backed by > > > huge pages. > > > > oh. As this is a performance patch, it would be much better if its > > description contained some performance measurement results! Please. > > > > I ran these patches through STREAM (http://www.cs.virginia.edu/stream/). > STREAM itself was patched to allocate data from the stack instead of statically > for the test. They completed without any problem on x86, x86_64 and PPC64 > and each test showed a performance gain from using hugepages. I can post > the raw figures but they are not currently in an eye-friendly format. Here > are some plots of the data though; > > x86: http://www.csn.ul.ie/~mel/postings/stack-backing-20080730/x86-stream-stack.ps > x86_64: http://www.csn.ul.ie/~mel/postings/stack-backing-20080730/x86_64-stream-stack.ps > ppc64-small: http://www.csn.ul.ie/~mel/postings/stack-backing-20080730/ppc64-small-stream-stack.ps > ppc64-large: http://www.csn.ul.ie/~mel/postings/stack-backing-20080730/ppc64-large-stream-stack.ps > > The test was to run STREAM with different array sizes (plotted on X-axis) > and measure the average throughput (y-axis). In each case, backing the stack > with large pages with a performance gain.
So about a 10% speedup on x86 for most STREAM configurations. Handy - that's somewhat larger than most hugepage-conversions, iirc.
Do we expect that this change will be replicated in other memory-intensive apps? (I do).
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