Messages in this thread |  | | Subject | Re: [Lse-tech] Re: (RFC): SKB Initialization | From | "Mala Anand" <> | Date | Fri, 23 Aug 2002 09:44:23 -0500 |
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Dave Hansen wrote.. >Mala Anand wrote: >> The third scope would be measuring this patch in a workload environment. >> We measured it in a web serving workload and found that we get 0.7% >> improvement.
>First of all, the patch doesn't apply at all against the current >bitkeeper tree. I can post the exact one I used if you like.
>I tried this under our Specweb99 setup. Here's a snippet of >readprofile with, then without the patch:
>alloc:free ratio: 1.226 >(__kfree_skb+alloc_skb)/total = 3.14%
>alloc:free ratio: 0.348 >(__kfree_skb+alloc_skb)/total = 2.79%
>You can see the entire readprofile here: >http://www.sr71.net/~specweb99/run-specweb-100sec-2400-2.5.31-bk+4-kmap-08-22-2002-11.20.17/
>http://www.sr71.net/~specweb99/run-specweb-100sec-2400-2.5.31-bk+4-kmap-mala-08-22-2002-11.44.25/
>No, I don't know why I have so much idle time.
Readprofile ticks are not as accurate as the cycles I measured. Moreover readprofile can give misleading information as it profiles on timer interrupts. The alloc_skb and __kfree_skb call memory management routines and interrupts are disabled in many parts of that code. So I don't trust the readprofile data.
Regards, Mala
Mala Anand IBM Linux Technology Center - Kernel Performance E-mail:manand@us.ibm.com http://www-124.ibm.com/developerworks/opensource/linuxperf http://www-124.ibm.com/developerworks/projects/linuxperf Phone:838-8088; Tie-line:678-8088
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