I found that dbench gives significantly lower numbers when
the partition on which it is run is mounted as ext3.
Here are some results, using the 2.5.28 kernel.
The hardware is dual p3, 1Ghz, 1GB memory, SCSI disks.
1st column is dbench clients.
2nd column is throughput with /home as ext2.
3rd column is throughput with /home as ext3 and data=writeback.
4th column is throughput with /home as ext3 and data=ordered.
The first set of data is from the test run right after boot.
The second set of data is from the test repeated immediately after
the first run. I used time -v dbench x, and ran vmstat after
each dbench run, so that output is available if needed. I can
rerun these tests looking at any specific vm stats which might be
of interest.
The short answer may be that dbench is not a reliable benchmark
for comparing filesystems. Or there may be something else more
interesting happening.
Steven
Ext2 writeback ordered
1 97.4729 66.8692 80.6777
2 173.776 115.785 78.4331
3 169.716 131.403 55.9812
4 182.292 137.741 54.0658
6 182.9 140.096 51.7433
8 185.994 136.422 45.8054
10 185.835 139.128 39.9597
12 190.126 136.411 47.4232
16 188.184 108.701 40.6673
20 154.191 99.8339 37.2275
24 143.686 59.2361 33.4655
28 153.039 56.741 43.1158
32 128.06 43.6015 41.6765
36 100.212 38.4583 35.9686
40 99.3539 39.8462 36.7342
44 93.8014 38.1305 30.2785
48 95.3078 33.0158 32.7519
52 83.2341 29.6972 34.3698
56 86.8121 31.4319 35.6022
64 86.2708 28.6704 35.851
80 61.82 23.4508 29.9819
96 55.1902 20.3729 25.9
112 49.4728 18.9149 25.9441
128 45.5107 17.8682 25.5909
Ext2 writeback ordered
1 112.486 90.063 88.4505
2 180.415 137.191 64.5044
3 187.655 142.127 66.5859
4 187.532 143.339 87.0815
6 192.05 142.317 50.8091
8 194.123 145.15 58.4781
10 193.88 107.345 52.4863
12 196.477 145.3 75.8064
16 196.05 119.826 38.7418
20 194.808 105.656 37.2839
24 194.146 80.4529 42.4934
28 159.703 56.2274 36.4412
32 141.214 47.6162 31.9981
36 126.962 45.0119 39.2894
40 95.749 34.4893 34.5664
44 90.348 30.5858 31.1847
48 94.087 34.1891 37.1048
52 87.3876 31.4304 34.8207
56 86.7181 30.9259 35.7337
64 86.682 26.9397 30.3703
80 54.4207 22.8923 31.7975
96 53.1359 20.1692 28.6667
112 52.1108 18.8062 24.6706
128 45.2542 * 22.2984
* unexpected power outage during 128 clients 2nd run with data=writeback.
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This archive was generated by hypermail 2b29 : Tue Jul 30 2002 - 14:00:24 EST