Messages in this thread | | | From | Mark_H_Johnson@Raytheon ... | Subject | Re: Real-Time Preemption, comparison to 2.6.10-mm1 | Date | Wed, 5 Jan 2005 11:52:06 -0600 |
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K.R. Foley wrote: >Mark_H_Johnson@raytheon.com wrote: [snip - long explanation of how a nice application can starve a non nice application for minutes at a time on an SMP system]
>> My point was that -mm definitely has the problem (though to a lesser >> degree). The tests I ran showed it on both the disk read and disk copy >> stress tests. I guess I should try a vanilla 2.6.10 run as well to see >> if it is something introduced in the -mm series (it certainly is not a >> recent change...). > >I'm curious if anyone is seeing this behavior on UP systems, or is it >only happening on SMP? The build of 2.6.10 vanilla just completed and I reran my tests with SMP and with MAXCPUS=1 (UP w/ SMP kernel).
The vanilla 2.6.10 kernel has the non RT starvation problem as well for both test runs. It looks like this is not something in -mm but a change between 2.4 and 2.6.
I did notice the test results were a little inconsistent between the two runs... 2.6.10 SMP 2.6.10 UP (w/ SMP kernel) disk write starved OK disk copy OK starved disk read starved starved but in both cases, a non nice (non RT) disk application was starved by a nice (non RT) cpu application for minutes.
I wonder who I should be talking to next (or submit a bug report?) about this.
--Mark
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