[MMTests] Threaded IO Performance on ext3

From: Mel Gorman
Date: Mon Jul 23 2012 - 17:24:57 EST

Configuration: global-dhp__io-threaded-ext3
Result: http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-threaded-ext3
Benchmarks: tiobench


Some good results but some 3.x kernels were bad and this varied between
machines. In some, 3.1 and 3.2 were particularly bad. 3.4 regressed on
one machine with a large amount of memory.

Benchmark notes

mkfs was run on system startup. No attempt was made to age it. No
special mkfs or mount options were used.

The size parameter for tiobench was 2*RAM. This is barely sufficient for
this particular test where the size parameter should be multiple
times the size of memory. The running time of the benchmark is
already excessive and this is not likely to be changed.

Machine: arnold
Result: http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-threaded-ext3/arnold/comparison.html
Arch: x86
CPUs: 1 socket, 2 threads
Model: Pentium 4
Disk: Single Rotary Disk

This has regressed in almost all cases although for this machine the
main damage was between 2.6.32 and 2.6.34. 3.2.9 performed particularly
badly. It's interesting to note that 3.1 and 3.2 kernels both swapped
and unexpected swapping has been seen in other tests.

Machine: hydra
Result: http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-threaded-ext3/hydra/comparison.html
Arch: x86-64
CPUs: 1 socket, 4 threads
Model: AMD Phenom II X4 940
Disk: Single Rotary Disk

This is a mixed bag. For low numbers of clients, throughput on
sequential reads has improved with the exception of 3.2.9 which
was a disaster. For larger number of clients, it is a mix of
gains and losses. This could be due to weakness in the methodology
due to both a small filesize and a small number of iterations.

Random read has improved.

With the exception of 3.2.9, sequential writes have generally

Random write has a number of regressions and 3.2.9 is a diaster.

Kernels 3.1 and 3.2 had unexpected swapping.

Machine: sandy
Result: http://www.csn.ul.ie/~mel/postings/mmtests-20120424/global-dhp__io-threaded-ext3/sandy/comparison.html
Arch: x86-64
CPUs: 1 socket, 8 threads
Model: Intel Core i7-2600
Disk: Single Rotary Disk


Like hydra, sequential reads were generally better for low numbers of
clients. 3.4 is notable in that it regressed. Unlike hydra, 3.1 was
the first bad kernel for sequential reads unlikely hydra where it was
3.2. There are differences in the memory sizes and therefore the filesize
and it implies that there is not a single cause of the regression.

Random read has improved.

Sequential writes have generally improved although it is interesting
to note that 3.1 was a kernel that regressed. 3.4 is better than 2.6.32
but it is interesting to note that it has regressed in comparison to 3.3.

Random write has generally improved but again 3.4 is worse than 3.3.

Like the other machines, 3.1 and 3.2 saw unexpected swapping.

Mel Gorman
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