Messages in this thread | | | Date | Tue, 10 Jun 2003 09:05:30 -0500 | From | Steven Pratt <> | Subject | Re: 2.5.70-mm2 causes performance drop of random read O_DIRECT |
| |
Nick Piggin wrote:
> Steven Pratt wrote: > >> 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. > > Hi Steven, this is quite likely to be an io scheduler problem. > Is your test program rawread v2.1.5?
This test was actually using 2.1.4, but the only difference in the 2.1.5 version is a fix for the test label array for the aio versions of the test. No functional change, just fixed the outputed test description.
> What is the command line you are using to invoke the program?
rawread -t6 -p8 -m1 -d2 -s4096 -n65536 -l1 -z -x
Which you can find if you follow either results link and look in the benchmark directory where all raw benchmark out put is stored.
Steve
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |