Messages in this thread | | | Date | Tue, 13 Apr 2004 23:59:40 +0200 | From | Andrea Arcangeli <> | Subject | Re: Benchmarking objrmap under memory pressure |
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On Tue, Apr 13, 2004 at 12:51:11AM -0700, Andrew Morton wrote: > "Martin J. Bligh" <mbligh@aracnet.com> wrote: > > > > UP Athlon 2100+ with 512Mb of RAM. Rebooted clean before each test > > then did "make clean; make vmlinux; make clean". Then I timed a > > "make -j 256 vmlinux" to get some testing under mem pressure. > > > > I was trying to test the overhead of objrmap under memory pressure, > > but it seems it's actually distinctly negative overhead - rather pleasing > > really ;-) > > > > 2.6.5 > > 225.18user 30.05system 6:33.72elapsed 64%CPU (0avgtext+0avgdata 0maxresident)k > > 0inputs+0outputs (37590major+2604444minor)pagefaults 0swaps > > > > 2.6.5-anon_mm > > 224.53user 26.00system 5:29.08elapsed 76%CPU (0avgtext+0avgdata 0maxresident)k > > 0inputs+0outputs (29127major+2577211minor)pagefaults 0swaps > > A four second reduction in system time caused a one minute reduction in > runtime? Pull the other one ;) > > Average of five runs, please...
at the very least the 6 seconds difference on a ~6 minutes load between anonvma and anonmm sounds smaller than the measurement error generated by disk seeks for a swapping workload, so yes, I'd like to see all 5 runs (not just the average).
As for the difference between 2.6.5 and 2.6.5-anonvma, that might be the memory saved by the removal of rmap that in turn reduces the swap-I/O required to complete the load or something like that, so that one may not be a measurement error but just the benefit of anon-vma or anonmm, but for a 6 seconds difference during a swap load I'd definitely like to see the 5 runs.
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