[Lustre-devel] Lustre RPC visualization

Michael Kluge Michael.Kluge at tu-dresden.de
Sun May 16 22:59:01 PDT 2010

Hi Galen,

that's why we started this :) I guess I need some more input data to be
able to play with the visualization. Vampir also supports markers that
can point to specific (process,timestamp) combinations. If we know that
some kind of condition happened while we collected the trace, it is
probably possible to detect this in the trace converter and to put a
mark into the trace file. That would help finding "interesting points"

Regards, Michael

Am Sonntag, den 16.05.2010, 23:39 -0400 schrieb Shipman, Galen M.: 
> I would be very interested in this, particularly at scale. We should look into collecting some large scale traces on Jaguar for experimentation of various visualization techniques.
> Thanks,
> Galen
> On May 16, 2010, at 9:12 AM, Eric Barton wrote:
> Excellent :)
> How do you think measurements taken from 1000 servers with 100,000
> clients can be visualised?  We've used heat maps to visualise
> 10s-100s of concurrent measurements (y) over time (x) but I wonder
> if that will scale.  Does vampire support heat maps?
>    Cheers,
>              Eric
> -----Original Message-----
> From: Michael Kluge [mailto:Michael.Kluge at tu-dresden.de]
> Sent: 16 May 2010 10:30 AM
> To: di.wang
> Cc: Eric Barton; Andreas Dilger; Robert Read; Galen M. Shipman; lustre-devel
> Subject: Re: [Lustre-devel] Lustre RPC visualization
> Hi WangDi,
> the first version works. Screenshot is attached. I have a couple of
> counter realized: RPC's in flight and RPC's completed in total on the
> client, RPC's enqueued, RPC's in processing and RPC'c completed in total
> on the server. All these counter can be broken down by the type of RPC
> (op code). The picture has not yet the lines that show each single RPC,
> I still have to do counter like "avg. time to complete an RPC over the
> last second" and there are some more TODO's. Like the timer
> synchronization. (In the screenshot the first and the last counter show
> total values while the one in the middle shows a rate.)
> What I like to have is a complete set of traces from a small cluster
> (<100 nodes) including the servers. Would that be possible?
> Is one of you in Hamburg May, 31-June, 3 for ISC'2010? I'll be there and
> like to talk about what would be useful for the next steps.
> Regards, Michael
> Am 03.05.2010 21:52, schrieb di.wang:
> Michael Kluge wrote:
> One more question: RPC 1334380768266400 (in the log WangDi sent me)
> has on the client side only a "Sending RPC" message, thus missing the
> "Completed RPC". The server has all three (received,start work, done
> work). Has this RPC vanished on the way back to the client? There is
> no further indication what happend. The last timestamp in the client
> log is:
> 1272565368.228628
> and the server says it finished the processing of the request at:
> 1272565281.379471
> So the client log has been recorded long enough to contain the
> "Completed RPC" message for this RPC if it arrived ever ...
> Logically, yes. But in some cases, some debug logs might be abandoned
> for some reasons(actually, it happens not rarely), and probably you need
> maintain an average time from server "Handled RPC" to client "Completed
> RPC", then you just guess the client "Completed RPC" time in this case.
> Oh my gosh ;) I don't want to start speculations about the helpfulness
> of incomplete debug logs. Anyway, what can get lost? Any kind of
> message on the servers and clients? I think I'd like to know what
> cases have to be handled while I try to track individual RPC's on
> their way.
> Any records can get lost here. Unfortunately, there are not any messages
> indicate the missing happened. :(
> (Usually, I would check the time stamp in the log, i.e. no records for a
> "long" time, for example several seconds, but this is not the accurate
> way).
> I guess you can just ignore these uncompleted records in your first
> step? Let's see how these incomplete log will
> impact the profiling result, then we will decide how to deal with this?
> Thanks
> Wangdi
> Regards, Michael
> _______________________________________________
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> --
> Michael Kluge, M.Sc.
> Technische Universität Dresden
> Center for Information Services and
> High Performance Computing (ZIH)
> D-01062 Dresden
> Germany
> Contact:
> Willersbau, Room WIL A 208
> Phone:  (+49) 351 463-34217
> Fax:    (+49) 351 463-37773
> e-mail: michael.kluge at tu-dresden.de<mailto:michael.kluge at tu-dresden.de>
> WWW:    http://www.tu-dresden.de/zih
> Galen M. Shipman
> Group Leader - Technology Integration
> National Center for Computational Sciences
> Oak Ridge National Laboratory
> Office: 865.576.2672
> Cell:   865.307.1209
> Email:  gshipman at ornl.gov<mailto:gshipman at ornl.gov>


Michael Kluge, M.Sc.

Technische Universität Dresden
Center for Information Services and
High Performance Computing (ZIH)
D-01062 Dresden

Willersbau, Room A 208
Phone:  (+49) 351 463-34217
Fax:    (+49) 351 463-37773
e-mail: michael.kluge at tu-dresden.de
WWW:    http://www.tu-dresden.de/zih
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