Re: New MPI benchmark performance results (update)

[xuehai zhang <hai@cs.uchicago.edu>]

Hi Nivedita,

Thanks for the response and the suggestion!

>> Hi all,
>>
>> In the following post I sent in early April 
>> (http://lists.xensource.com/archives/html/xen-devel/2005-04/msg00091.html), 
> 
> 
> 
> Hi, thanks for sharing the data - it was interesting.
> I tried to find additional data on the benchmarks using
> the link you have for the user manual but it gave me
> a 404 Error. 

I corrected the link error and now you can access the user manual through the link.

> It wasn't clear whether your benchmarks
> use TCP or UDP or possibly raw sockets?

I've read through the PMB user manual and it doesn't mention the communication protocol it uses. 
However, I do read "typically TCP/IP is the protocol used over Ethernet networks for MPI 
communications" from several references.

> As has been pointed out by several people, running the
> 2.6 kernel and comparing apples to apples as much as possible
> would help.

I fully agree with that and currently I try to rerun the experiments by using the same kernel 
versions for both dom0 and domU (maybe native linux too).
> 
> Is there any chance you kept some of the system statistics
> and settings (netstat -s, sysctl -a info)?.

I did not collect them while running the benchmarks, but I will try to log them when I rerun the 
experiments.

> Did you tune the settings for the system at all?
No, I did not do any specific things to tune the system.

>> Alltoall latency (max domU/linux > 60). The performance difference in 
>> the last example is HUGE and we could not think about a reasonable 
>> explaination why transferring 512B message size is so much different 
>> than other sizes. We appreciate if you can provide your insight to 
>> such a big performance problem in these benchmarks.
> 
> 
> You have an anomalous point on most of the results - and again,
> knowing what kind of traffic this is would really help.

I will try to dig into the source code and find it out.

Thanks again for the help.

Xuehai
> 
> thanks,
> Nivedita
> 
> 
> 
> 
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