Hi Gerrit,
Thanks a lot. This patch has really helped.
--
Regards,
Upakul Barkakaty
On 5/2/08, Gerrit Renker <[EMAIL PROTECTED]> wrote:
>
> Upakul,
>
> thank you for testing. So it seems the problem is not in this corner. I
> also recall comparing the performance of iperf 2.0.4 against 2.0.2 with
> that patch - Jon has added some condition variables, which seem to have
> a similar effect (testing with 2.0.4 also gave modest CPU usage).
>
> With regard to the delay loop, the high CPU consumption seems clear
> since delay_loop() constantly calls gettimeofday(), i.e. issueing the
> same system call over and over again in a busy-wait loop. Which agrees
> with your analysis.
>
> I have had problems with this, too, but in a different corner: when
> measuring the actual times, delay_loop() sometimes added something like
> 50 milliseconds at random times, which seems like a quantum for a
> context switch.
>
> It got much better when replacing the busy-wait loop with a call to the
> Posix function nanosleep(), since this uses hrtimers internally and
> blocks signals.
>
> Although the patch was initially not intended to reduce CPU usage, I
> could well imagine that it does since removes the busy-wait loop.
>
> If you have a moment of time, could you check out whether this makes a
> difference -- it is in the repository, on
>
>
> https://sourceforge.net/tracker/index.php?func=detail&aid=1940009&group_id=128336&atid=711373
>
> Best regards
>
> Gerrit
>
> Quoting Upakul Barkakaty:
> | Hi Gerrit,
> |
> | Thanks a lot for your reply. I indeed tried out the patch but it did
> not
> | make any difference. I am still seeing 0% CPU Idle.
> |
> | It looks to me as if the delay_loop() function in the file Client.cpp
> is
> | holding the processor in the kernel space while adjusting the
> thoughput
> | speeds, resulting in 0% CPU Idle. On trying out replacing
> delay_loop() by
> | usleep() function, Idle MIPS were seen to be available. Or perhaps is
> it
> | the case that iperf should be used only for throughput measurement
> and
> | might not be so appropriate for measuring the cpu utilization?
> |
> | --
> | Regards,
> | Upakul Barkakaty
> |
> | On 5/2/08, Gerrit Renker <[EMAIL PROTECTED]> wrote:
> |
> | Dear Upakul,
> |
> | if it is not too much of a bother, can you please check if the
> attached
> | patch fixes the CPU usage problem?
> |
> | It is a port of Ingo Molnar's CPU usage fix - we have used that
> patch in
> | iperf with great benefit (the CPU usage went down to very modest
> | values).
> |
> | Regards
> | Gerrit
> |
> | Quoting Upakul Barkakaty:
> | | Hi Jon,
> | |
> | | I have upgraded to Iperf-v2.0.4. But unfortunately, even with
> this
> | version
> | | I observed that the Iperf client was consuming all the CPU
> MIPS
> | even if it
> | | was running at 1 Mbps.
>
>
>
> The University of Aberdeen is a charity registered in Scotland, No
> SC013683.
>
>
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