Re: [OMPI devel] Affect of compression on modex and launch messages

On 4/7/08 7:45 AM, "Gleb Natapov" wrote: > On Mon, Apr 07, 2008 at 07:28:07AM -0600, Ralph H Castain wrote: >>> Also can you explain how >>> allgather is implemented in orte (sorry if you already explained this once >>> and I missed it). >> >> The default method is for

Re: [OMPI devel] Affect of compression on modex and launch messages

On Mon, Apr 07, 2008 at 07:28:07AM -0600, Ralph H Castain wrote: > > Also can you explain how > > allgather is implemented in orte (sorry if you already explained this once > > and I missed it). > > The default method is for each proc to send its modex data to its local > daemon. The local daemon

Re: [OMPI devel] Affect of compression on modex and launch messages

On 4/7/08 7:15 AM, "Gleb Natapov" wrote: > On Mon, Apr 07, 2008 at 07:07:38AM -0600, Ralph H Castain wrote: >> >> >> >> On 4/7/08 7:04 AM, "Gleb Natapov" wrote: >> >>> On Fri, Apr 04, 2008 at 10:52:38AM -0600, Ralph H Castain wrote: With

Re: [OMPI devel] Affect of compression on modex and launch messages

On Mon, Apr 07, 2008 at 07:07:38AM -0600, Ralph H Castain wrote: > > > > On 4/7/08 7:04 AM, "Gleb Natapov" wrote: > > > On Fri, Apr 04, 2008 at 10:52:38AM -0600, Ralph H Castain wrote: > >> With compression "on", you will get output telling you the original size of > >>

Re: [OMPI devel] Affect of compression on modex and launch messages

actually, we used lzo a looong time ago with PACX-MPI, it was indeed faster then zlib. Our findings at that time were however similar to what George mentioned, namely a benefit from compression was only visible if the network latency was really high (e.g. multiple ms)... Thanks Edgar Roland

Re: [OMPI devel] Affect of compression on modex and launch messages

LZO looks cool, but it's unfortunately GPL (Open MPI is BSD). Bummer. On Apr 4, 2008, at 2:29 PM, Roland Dreier wrote: Based on some discussion on this list, I integrated a zlib-based compression ability into ORTE. Since the launch message sent to the orteds and the modex between the

Re: [OMPI devel] Affect of compression on modex and launch messages

> Based on some discussion on this list, I integrated a zlib-based compression > ability into ORTE. Since the launch message sent to the orteds and the modex > between the application procs are the only places where messages of any size > are sent, I only implemented compression for those two

Re: [OMPI devel] Affect of compression on modex and launch messages

Ralph, There are several studies about compressions and data exchange. Few years ago we integrate such mechanism (adaptive compression of communication) in one of the projects here at ICL (called GridSolve). The idea was to optimize the network traffic for sending large matrices used for