Re: HAMMER problems with ciss
On 08/08/2009, Matthew Dillon <dillon@apollo.backplane.com> wrote:
> It will depend on what kind of test you are running. Anything
> that calls fsync() is going to be fairly horrible for HAMMER...
> flushing the filesystem is very expensive and going to remain
> that way for a while.
>
> Normal sequential write I/O without fsync() should be fairly close
> to platter rates, at least that is what I get, e.g. with something
> like dd.
Sysbench, and yes, it calls fsync. I get about half of the UFS performance data.
dd is OK.
The performance is also lower when reading, here are some lines from
the random read test:
dfly hammer:
#bklsize[kB] MBps iops min avg max 95% -
latency times in ms
1 .14 150.77 0.0000 0.0066 2.4605 0.0101
2 .34 177.72 0.0000 0.0056 1.5467 0.0083
4 .64 165.02 0.0000 0.0060 2.7946 0.0087
8 1.39 179.03 0.0000 0.0056 0.0179 0.0084
16 2.59 166.17 0.0000 0.0060 4.1047 0.0086
32 4.81 153.94 0.0000 0.0065 0.8895 0.0103
64 10.59 169.49 0.0000 0.0059 2.5563 0.0085
128 15.54 124.35 0.0001 0.0080 3.3134 0.0117
256 29.90 119.61 0.0001 0.0083 2.2407 0.0116
fbsd8 UFS:
#bklsize[kB] MBps iops min avg max 95% -
latency times in ms
1 .20 212.32 0.01 4.71 833.94 7.62
2 .40 206.95 0.01 4.83 321.63 7.84
4 .84 216.99 0.01 4.60 1751.44 7.47
8 1.65 211.71 0.01 4.72 321.55 7.66
16 3.34 214.37 0.01 4.66 245.09 7.54
32 6.34 203.13 0.01 4.92 570.37 7.88
64 11.66 186.58 0.02 5.36 516.09 8.40
128 20.30 162.41 0.04 6.15 517.97 9.41
256 34.13 136.54 0.07 7.32 667.05 10.74
This is with a P400, 512 MiB BBWC and a 15k RPM SAS disk.
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