Messages in this thread | ![/](/images/icornerl.gif) | | Date | Mon, 29 Mar 2004 21:35:42 +0200 | From | Andreas Hartmann <> | Subject | Re: Very poor performance with 2.6.4 |
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Chris Mason wrote: > On Mon, 2004-03-29 at 01:16, Andreas Hartmann wrote: >> Andrew Morton wrote: >> > Andreas Hartmann <andihartmann@freenet.de> wrote: >> >> >> >> I tested kernel 2.6.4. While compiling kdelibs and kdebase, I felt, that >> >> kernel 2.6 seems to be slower than 2.4.25. >> >> >> >> So I did some tests to compare the performance directly. Therefore I >> >> rebooted for everey test in init 2 (no X). >> >> >> >> I locally compiled 2.6.5rc2 3 times under 2.6.4 and under 2.4.25 on a >> >> reiserfs LVM partition, which resides onto a IDE HD (using DMA) and got >> >> the following result: >> >> >> >> In the middle, compiling under kernel 2.6.4 tooks 9.3% more real time than >> >> under 2.4.25. >> >> The user-processortime is about the same, but the system-processortime is >> >> under 2.6.4 32.9% higher than under 2.4.25. >> > >> > Try mounting your reiserfs filesystems with the `-o nolargeio=1' option. >> >> This didn't help. >> >> > >> > If that doesn't help, please run a comparative kernel profile. See >> > Documentation/basic_profiling.txt. >> >> I'll do this next. > > You might also want to try 2.6.5-rc2 which has a set of reiserfs fixes > from 2.4.x. I'm hoping those will clean things up for you.
Ok, here is the result for 2.6.5-rc2 (3 times middle, with preemption), compared to 2.4.25.
The result is, the performancedifference to 2.4.25 is the same as for 2.6.4 as described above. Nearly means: The real processing time is about 1% faster than under 2.6.4, but 8.3% slower than with 2.4.25. The system-processortime is 1.2% faster than under 2.6.4 but 31,7% more than under 2.4.25. The times for the user-processortime is unchanged.
But I'm not shure if these values are really significant, because the values for the real time meassured each try differ a lot under 2.6.
For example 2.6.5rc2: between 9.07 min and 8.37 min for real time. Under 2.4.25, the differences are a lot of smaller: between 8.06 min and 8.15 min for real time. The values for user and system time are nearly constant with 6.49 min and 36 sec (kernel 2.6) and 6.43 min / 27 sec for 2.4.25.
Regards, Andreas Hartmann - 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/
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