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SubjectRe: [Ext2-devel] Re: [RFC][PATCH 0/2]Extend ext3 filesystem limit from 8TB to 16TB
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Le mar 18/04/2006 à 23:01, Mingming Cao a écrit :
> On Tue, 2006-04-18 at 09:30 +0200, Arjan van de Ven wrote:
> > On Tue, 2006-04-18 at 09:14 +0200, Laurent Vivier wrote:
> > > Le lun 17/04/2006 à 23:32, Ravikiran G Thirumalai a écrit :
> > > > On Mon, Apr 17, 2006 at 11:09:36PM +0200, Arjan van de Ven wrote:
> > > > > On Mon, 2006-04-17 at 14:07 -0700, Ravikiran G Thirumalai wrote:
> > > > > >
> > > > > >
> > > > > > I ran the same tests on a 16 core EM64T box very similar to the one
> > > > > > you ran
> > > > > > dbench on :). Dbench results on ext3 varies quite a bit. I couldn't
> > > > > > get
> > > > > > to a statistically significant conclusion For eg,
> > > > >
> > > > >
> > > > > dbench is not a good performance benchmark. At all. Don't use it for
> > > > > that ;)
> > > >
> > > > Agreed. (I did not mean to use it in the first place :). I was just trying
> > > > to verify the benchmark results posted earlier)
> > > >
> > > > Thanks,
> > > > Kiran
> > >
> > > What is the good performance benchmark to know if we should use atomic_t
> > > instead of percpu_counter ?
> >
> > you probably want something like postal/postmark instead or so (although
> > that's not ideal either), at least that's reproducable
> >
> postmark is a single threaded benchmark.
>
> The ext3 filesystem free blocks counter is mostly being updated at block
> allocation and free code. So, a test with many many threads doing block
> allocation/deallocation simultaneously will stress the free blocks
> counter accounting better than a single threaded fs benchmark. After
> all, the main reason we choose to use percpu counter for the free blocks
> counter at the first place, I believe, was to support parallel block
> allocation.
>
> I would suggest run tiobench with many threads (>256), or even better,
> run tiobench with many dd tests at the background.

You can find attached my results with tiobench (256 threads, always on
x440 with 8 CPUs hyperthreaded = 16).

But, as the results are very different, I think we can't really
conclude... in fact, I think atomic_t or percpu_counter have no impact
on the results.

Regards,
Laurent
--
Laurent Vivier
Bull, Architect of an Open World (TM)
http://www.bullopensource.org/ext4
tiobench.pl --size 16 --numruns 10 --threads 256

Unit information
================
File size = megabytes
Blk Size = bytes
Rate = megabytes per second
CPU% = percentage of CPU used during the test
Latency = milliseconds
Lat% = percent of requests that took longer than X seconds
CPU Eff = Rate divided by CPU% - throughput per cpu load

Sequential Reads
atomic_long_t 16 4096 256 394.38 1540.% 2.822 5960.36 0.00000 0.00000 26
atomic_long_t 16 4096 256 384.70 1547.% 2.087 6187.27 0.00000 0.00000 25
atomic_long_t 16 4096 256 395.69 1548.% 2.001 5988.64 0.00000 0.00000 26
atomic_long_t 16 4096 256 396.10 1544.% 1.987 5836.74 0.00000 0.00000 26
atomic_long_t 16 4096 256 377.66 1551.% 2.435 6038.05 0.00000 0.00000 24
atomic_long_t 16 4096 256 378.35 1550.% 2.145 6369.26 0.00000 0.00000 24
atomic_long_t 16 4096 256 375.38 1545.% 2.236 6318.84 0.00000 0.00000 24
atomic_long_t 16 4096 256 399.97 1546.% 2.021 5911.10 0.00000 0.00000 26
atomic_long_t 16 4096 256 386.59 1542.% 2.045 5968.13 0.00000 0.00000 25
atomic_long_t 16 4096 256 401.45 1547.% 2.000 5918.17 0.00000 0.00000 26
percpu_counter 16 4096 256 396.22 1539.% 1.965 5984.66 0.00000 0.00000 26
percpu_counter 16 4096 256 403.50 1547.% 2.373 5503.98 0.00000 0.00000 26
percpu_counter 16 4096 256 388.54 1547.% 2.047 6100.05 0.00000 0.00000 25
percpu_counter 16 4096 256 397.43 1540.% 2.096 6010.45 0.00000 0.00000 26
percpu_counter 16 4096 256 398.81 1543.% 2.134 5677.78 0.00000 0.00000 26
percpu_counter 16 4096 256 399.85 1548.% 1.980 5805.21 0.00000 0.00000 26
percpu_counter 16 4096 256 394.70 1551.% 2.021 5960.13 0.00000 0.00000 25
percpu_counter 16 4096 256 396.64 1543.% 2.132 5901.40 0.00000 0.00000 26
percpu_counter 16 4096 256 390.70 1550.% 1.906 5972.05 0.00000 0.00000 25
percpu_counter 16 4096 256 401.98 1547.% 2.049 5839.44 0.00000 0.00000 26


Random Reads
atomic_long_t 16 4096 256 100.79 1230.% 0.351 3.82 0.00000 0.00000 8
atomic_long_t 16 4096 256 112.61 1342.% 0.367 13.42 0.00000 0.00000 8
atomic_long_t 16 4096 256 111.16 1354.% 0.503 450.22 0.00000 0.00000 8
atomic_long_t 16 4096 256 112.79 1333.% 0.366 4.73 0.00000 0.00000 8
atomic_long_t 16 4096 256 114.61 1322.% 0.375 12.74 0.00000 0.00000 9
atomic_long_t 16 4096 256 111.18 1350.% 0.368 19.89 0.00000 0.00000 8
atomic_long_t 16 4096 256 112.14 1344.% 0.395 143.76 0.00000 0.00000 8
atomic_long_t 16 4096 256 112.41 1346.% 0.374 31.40 0.00000 0.00000 8
atomic_long_t 16 4096 256 112.89 1353.% 0.372 12.64 0.00000 0.00000 8
atomic_long_t 16 4096 256 112.40 1354.% 0.365 10.88 0.00000 0.00000 8
percpu_counter 16 4096 256 112.68 1341.% 0.439 263.93 0.00000 0.00000 8
percpu_counter 16 4096 256 109.77 1356.% 0.372 35.58 0.00000 0.00000 8
percpu_counter 16 4096 256 114.18 1339.% 0.371 29.47 0.00000 0.00000 9
percpu_counter 16 4096 256 112.61 1339.% 0.430 241.78 0.00000 0.00000 8
percpu_counter 16 4096 256 111.09 1343.% 0.372 46.84 0.00000 0.00000 8
percpu_counter 16 4096 256 111.98 1355.% 0.358 16.41 0.00000 0.00000 8
percpu_counter 16 4096 256 112.55 1348.% 0.393 121.30 0.00000 0.00000 8
percpu_counter 16 4096 256 114.84 1324.% 0.398 112.03 0.00000 0.00000 9
percpu_counter 16 4096 256 111.45 1353.% 0.368 22.09 0.00000 0.00000 8
percpu_counter 16 4096 256 112.21 1352.% 0.405 150.62 0.00000 0.00000 8

Sequential Writes
atomic_long_t 16 4096 256 28.72 350.0% 103.526 3087.83 0.00000 0.00000 8
atomic_long_t 16 4096 256 28.47 350.1% 107.563 4127.54 0.00000 0.00000 8
atomic_long_t 16 4096 256 28.10 346.6% 108.709 2767.21 0.00000 0.00000 8
atomic_long_t 16 4096 256 28.24 345.1% 106.619 3025.58 0.00000 0.00000 8
atomic_long_t 16 4096 256 28.35 358.4% 110.779 3844.84 0.00000 0.00000 8
atomic_long_t 16 4096 256 28.14 349.9% 109.956 3580.34 0.00000 0.00000 8
atomic_long_t 16 4096 256 28.23 349.6% 110.011 2770.21 0.00000 0.00000 8
atomic_long_t 16 4096 256 28.46 355.4% 108.701 2694.87 0.00000 0.00000 8
atomic_long_t 16 4096 256 28.14 346.3% 108.114 3461.73 0.00000 0.00000 8
atomic_long_t 16 4096 256 28.49 348.8% 109.625 3160.93 0.00000 0.00000 8
percpu_counter 16 4096 256 27.92 344.3% 109.420 3497.14 0.00000 0.00000 8
percpu_counter 16 4096 256 28.23 343.2% 110.146 3279.80 0.00000 0.00000 8
percpu_counter 16 4096 256 28.35 345.6% 110.027 3527.68 0.00000 0.00000 8
percpu_counter 16 4096 256 28.17 348.9% 107.143 3735.24 0.00000 0.00000 8
percpu_counter 16 4096 256 28.07 333.8% 107.581 2442.35 0.00000 0.00000 8
percpu_counter 16 4096 256 28.36 343.2% 106.625 2740.56 0.00000 0.00000 8
percpu_counter 16 4096 256 28.33 343.6% 107.201 3029.49 0.00000 0.00000 8
percpu_counter 16 4096 256 28.28 339.9% 107.849 3100.73 0.00000 0.00000 8
percpu_counter 16 4096 256 28.27 344.8% 108.008 3753.06 0.00000 0.00000 8
percpu_counter 16 4096 256 28.54 354.1% 108.254 2831.67 0.00000 0.00000 8

Random Writes
atomic_long_t 16 4096 256 2.47 64.55% 5.690 1295.08 0.00000 0.00000 4
atomic_long_t 16 4096 256 2.45 63.52% 6.021 1386.22 0.00000 0.00000 4
atomic_long_t 16 4096 256 2.47 63.87% 5.621 912.91 0.00000 0.00000 4
atomic_long_t 16 4096 256 2.45 64.34% 6.361 1444.26 0.00000 0.00000 4
atomic_long_t 16 4096 256 2.47 64.04% 5.793 1307.02 0.00000 0.00000 4
atomic_long_t 16 4096 256 2.47 64.14% 5.979 1690.00 0.00000 0.00000 4
atomic_long_t 16 4096 256 2.49 64.63% 5.993 1820.59 0.00000 0.00000 4
atomic_long_t 16 4096 256 2.48 64.98% 6.400 1829.93 0.00000 0.00000 4
atomic_long_t 16 4096 256 2.44 64.05% 5.763 1631.14 0.00000 0.00000 4
atomic_long_t 16 4096 256 2.53 66.19% 5.728 919.34 0.00000 0.00000 4
percpu_counter 16 4096 256 2.43 63.69% 5.927 851.10 0.00000 0.00000 4
percpu_counter 16 4096 256 2.42 62.73% 5.997 1371.13 0.00000 0.00000 4
percpu_counter 16 4096 256 2.46 64.17% 6.223 1808.24 0.00000 0.00000 4
percpu_counter 16 4096 256 2.46 64.04% 5.897 1410.98 0.00000 0.00000 4
percpu_counter 16 4096 256 2.47 63.98% 5.829 1197.30 0.00000 0.00000 4
percpu_counter 16 4096 256 2.48 64.15% 5.660 1079.85 0.00000 0.00000 4
percpu_counter 16 4096 256 2.47 63.81% 6.041 1401.02 0.00000 0.00000 4
percpu_counter 16 4096 256 2.48 64.88% 6.078 1218.58 0.00000 0.00000 4
percpu_counter 16 4096 256 2.49 64.90% 6.148 1468.47 0.00000 0.00000 4
percpu_counter 16 4096 256 2.47 65.64% 5.724 1148.28 0.00000 0.00000 4

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