Messages in this thread | | | Date | Thu, 2 Sep 2004 19:11:43 +0200 | From | Hendrik Fehr <> | Subject | PROBLEM: Full CPU-usage on sis5513-chipset disc input/output-operations |
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Hello! I was busying myself with this for about two weeks, and today i am likely to say that this is a bug in the kernel.
The symptoms for short: On 2.4.x (actually 2.4.27) kernel, disk i/o operations perform well (no noticable cpu overhead). But: on kernel 2.6.9-rc1-bk8 (and all the other 2.6.x that i tested), disk i/o operations perform bad: full cpu usage (sys) when copying files or doing other i/o operations.
And to make sure that the new scheduling interface is not the "bad guy" i tried different schedulers with elevator=<something>. The bug was still there.
That is what i was doing to resolve the problem: I wrote to Lionel (the sis5513.c author found in MAINTAINERS) on 20040831: ----8<----- I am using linux-2.6.x kernel with sis5513 support enabled. I discovered a strange performance problem that was mentioned on bugzilla.kernel.org some time before [1.]. For a full and details report you may have a look at [2.].
[1.] http://bugzilla.kernel.org/show_bug.cgi?id=2983 [2.] http://rcswww.urz.tu-dresden.de/~s4248297/gubed/report.html
I dont know if it is a problem of the sis5513.c code, but i hope you may be helpful in finding the right person to whom i should send this bug. ----8<-----
He tried to figure out, if this behaviour may be a problem of his driver, and it seems that this is not the case. He sugested that i may post this problem to this list, that is, what i am doing here. You can see the full conversation with Linonel at the web page at [2.]
IMHO it must have to do with the Uniform Multi-Platform E-IDE driver. The 2.4 kernel uses revision 7.00beta4-2.4 and the 2.6 uses revision 7.00alpha2. If this sugestion is wrong excuse me, i am not a C programer.
Everyone who is keen on solving this problem should have a look at the very detailed description of the bug on the web page [2.]. I kept it as close as possible to the rules in the REPORTING-BUGS file (hey i even made some screenshots). The question is: why would the same hardware combination on the 2.4 kernel perform well, and not so well on 2.6.
PS: please CC me, i am not on the list ;-)
Best regards, Hendrik Fehr. - 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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