Hi florin, I suspect this might have to do with your platform's AIO libraries being broken and us having to work around that. Could you try the alt-aio stuff and see if that improves things a bit? Sam, there are some config file settings for this, isn't it? I forget what we need to modify.. Would it make any difference if configure works around aio-threaded-callbacks?
I am really tempted to just write our own aio libraries and on-disk backends instead of relying on Linux/glibc and ext3..sigh Thanks, Murali On 7/17/07, Florin Isaila <[EMAIL PROTECTED]> wrote:
Hi Sam, we start the pvfs2 servers on different machines than the compute nodes (picking the nodes from the list provided by the batch system). Was that your question? And I should have said, all the measurements are done with collective I/O of ROMIO. On 7/17/07, Sam Lang <[EMAIL PROTECTED]> wrote: > > Ah, I read your email wrong. Hmm...so writes really tank. Are you > using the storage nodes as servers, or other compute nodes? > > -sam > > On Jul 17, 2007, at 11:15 AM, Sam Lang wrote: > > > > > Hi Florin, > > > > Just one clarification question...are those are bandwidth numbers > > not seconds as the plot label suggests? > > > > -sam > > > > On Jul 17, 2007, at 11:03 AM, Florin Isaila wrote: > > > >> Hi everybody, > >> > >> I have a question about the PVFS2 write performance. > >> > >> We did some measurements with BTIO over PVFS2 on lonestar at TACC > >> (http://www.tacc.utexas.edu/services/userguides/lonestar/) > >> > >> and we get pretty bad write results with classes B and C: > >> > >> http://www.arcos.inf.uc3m.es/~florin/btio.htm > >> > >> We used 16 I/O servers, the default configuration parameters and upto > >> 100 processes. We realized that all I/O servers were used also as > >> metadata servers, but BTIO uses just one file. > >> > >> The times are in seconds, contain only I/O time (no compute time) and > >> are aggregated per each BTIO run (BTIO performs several writes). > >> > >> TroveSyncMeta was set to yes (by default). Could this cause the I/ > >> O to > >> be serialized? It looks as if there were a serialization. > >> > >> Or could the fact that all nodes were also launched as metadata > >> managers affect the performance? > >> > >> Any clue why this happens? > >> > >> Many thanks > >> Florin > >> _______________________________________________ > >> Pvfs2-users mailing list > >> [email protected] > >> http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users > >> > > > > _______________________________________________ Pvfs2-users mailing list [email protected] http://www.beowulf-underground.org/mailman/listinfo/pvfs2-users
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