Starting in 2.5.70-mm2 and continuing in the mm tree, there is a
significant degrade in random read for block devices using O_DIRECT.
The drop occurs for all block sizes and ranges from 30%-40. CPU usage
is also lower although it may already be so low as to be irrelavent.
tolerance = 0.00 + 3.00% of 2.5.70-mm1
2.5.70-mm1 2.5.70-mm2
Blocksize KBs/sec KBs/sec %diff diff tolerance
---------- ------------ ------------ -------- ------------ ------------
4096 1567 924 -41.03 -643.00 47.01 *
8192 3057 1815 -40.63 -1242.00 91.71 *
16384 5745 3509 -38.92 -2236.00 172.35 *
65536 17357 11283 -34.99 -6074.00 520.71 *
262144 37537 27302 -27.27 -10235.00 1126.11 *
Full results can be found at:
http://www-124.ibm.com/developerworks/oss/linuxperf/regression/2.5.70-mm2/2.5.70-mm1-vs-2.5.70-mm2/
Steve
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This archive was generated by hypermail 2b29 : Sun Jun 15 2003 - 22:00:22 EST