Hello Jeff,

 

I would also like to add to Igor’s comment that CPU time shown by Google is a sum of all CPUs of distributed system involved in update operation (and who knows how many servers are involved?). Also they “define ‘CPU hour’ in terms of a hypothetical 1.4 GHz processor, whereas the actual processors we use in production vary but are generally faster than this” (see comment of DonSchwarz: http://groups.google.com/group/google-appengine-java/browse_thread/thread/aa9f18638b7bbea9?pli=1). According to the same topic 6.5 CPU hours is about 2.3 minutes real time. I think you may try to remove some of indexes which need to be updated on each new file upload (see Datastore Indexes on Web admin console).

 

Regards,

Andrew Senin.

 

From: Igor Ivanov [mailto:igor.ivanov@argus-cv.com]
Sent: Friday, February 12, 2010 6:02 PM
To: Jeff Squyres
Cc: Development list for the MPI Testing Tool; bg@argus-cv.com; Yiftah Shahar
Subject: Re: More GDS questions

 

Hi Jeff,

You touched a sore point. App engine forums are in filled  the questions as yours.
I can not know clear answer now.

Igor

Jeff Squyres wrote:

Igor et al. -- 
 
1. I'm not sure you saw Ethan's and my posts from the past day or so about GDS on the mtt-devel list; it just occurred to me that I don't know if you're members of the list or not.  We've posted a few questions and comments that you may not have received if you're not on the list:
 
    http://www.open-mpi.org/community/lists/mtt-devel/2010/02/index.php
 
2. I'm still looking into the perl syntax error that caused my Big Submit to GDS to fail.  But looking at the Google logs, it looks like at least *some* of my test run results made it up to GDS.  There was a BIG spike in CPU usage (3.2 hours of CPU time!) when it submitted -- see the attached CPU usage graph from the apps dashboard.
 
Does anyone know why it takes so much CPU just to submit data to GDS?  3.2 CPU hours is a LOT!
 
It makes me a bit concerned that only part of a single Cisco MTT run submit checked through almost half of our daily CPU quota (6.5 CPU hours/day).  Is there any way to reduce the amount of CPU necessary just to submit data?
 
  

 


 



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