Code is in (see r23633). Note: mmap is still the default.
--
Samuel K. Gutierrez
Los Alamos National Laboratory
On Aug 12, 2010, at 11:37 AM, Samuel K. Gutierrez wrote:
> Sorry, I should have included the link containing the discussion of
> the plot.
>
> http://www.open-mpi.org/community/lists/devel/2010/06/8078.php
>
> --
> Samuel K. Gutierrez
> Los Alamos National Laboratory
>
> On Aug 12, 2010, at 11:20 AM, Terry Dontje wrote:
>
>> Sorry Rich, I didn't realize there was a graph attached at the end
>> of message. In other words my comments are not applicable because
>> I really didn't know you were asking about the graph. I agree it
>> would be nice to know what the graph was plotting.
>>
>> --td
>> Terry Dontje wrote:
>>>
>>> Graham, Richard L. wrote:
>>>>
>>>> Stupid question:
>>>> What is being plotted, and what are the units ?
>>>>
>>>> Rich
>>>>
>>> MB of Resident and Shared memory as gotten from top (on linux).
>>> The values for each of the processes run cases seem to be the same
>>> between posix, mmap and sysv.
>>>
>>> --td
>>>> On 8/11/10 3:15 PM, "Samuel K. Gutierrez" <samuel_at_[hidden]> wrote:
>>>>
>>>> Hi Terry,
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> On Aug 11, 2010, at 12:34 PM, Terry Dontje wrote:
>>>>
>>>>
>>>> I've done some minor testing on Linux looking at resident and
>>>> shared memory sizes for np=4, 8 and 16 jobs. I could not see any
>>>> appreciable differences in sizes in the process between sysv,
>>>> posix or mmap usage in the SM btl.
>>>>
>>>> So I am still somewhat non-plussed about making this the
>>>> default. It seems like the biggest gain out of using posix might
>>>> be one doesn't need to worry about the location of the backing
>>>> file. This seems kind of frivolous to me since there is a
>>>> warning that happens if the backing file is not memory based.
>>>>
>>>> If I'm not mistaken, the warning is only issued if the backing
>>>> files is stored on the following file systems: Lustre, NFS,
>>>> Panasas, and GPFS (see: opal_path_nfs in opal/util/path.c).
>>>> Based on the performance numbers that Sylvain provided on June
>>>> 9th of this year (see attached), there was a performance
>>>> difference between mmap on /tmp and mmap on a tmpfs-like file
>>>> system (/dev/shm in that particular case). Using the new POSIX
>>>> component provides us with a portable way to provide similar
>>>> shared memory performance gains without having to worry about
>>>> where the OMPI session directory is rooted.
>>>>
>>>> --
>>>> Samuel K. Gutierrez
>>>> Los Alamos National Laboratory
>>>>
>>>> [cid:3364459484_11867134]
>>>>
>>>>
>>>> I still working on testing the code on Solaris but I don't
>>>> imagine I will see anything that will change my mind.
>>>>
>>>> --td
>>>>
>>>> Samuel K. Gutierrez wrote:
>>>> Hi Rich,
>>>>
>>>> It's a modification to the existing common sm component. The
>>>> modifications do include the addition of a new POSIX shared
>>>> memory facility, however.
>>>>
>>>> Sam
>>>>
>>>> On Aug 11, 2010, at 10:05 AM, Graham, Richard L. wrote:
>>>>
>>>>
>>>> Is this a modification of the existing component, or a new
>>>> component ?
>>>>
>>>> Rich
>>>>
>>>>
>>>> On 8/10/10 10:52 AM, "Samuel K. Gutierrez" <samuel_at_[hidden]> <mailto:samuel_at_[hidden]
>>>> > wrote:
>>>>
>>>> Hi,
>>>>
>>>> I wanted to give everyone a heads-up about a new POSIX shared
>>>> memory
>>>> component
>>>> that has been in the works for a while now and is ready to be
>>>> pushed
>>>> into the
>>>> trunk.
>>>>
>>>> http://bitbucket.org/samuelkgutierrez/ompi_posix_sm_new
>>>>
>>>> Some highlights:
>>>> o New posix component now the new default.
>>>> o May address some of the shared memory performance
>>>> issues users
>>>> encounter
>>>> when OMPI's session directories are inadvertently
>>>> placed on a non-
>>>> local
>>>> filesystem.
>>>> o Silent component failover.
>>>> o In the default case, if the posix component fails
>>>> initialization,
>>>> mmap will be selected.
>>>> o The sysv component will only be queried for selection if it is
>>>> placed before
>>>> the mmap component (for example, -mca mpi_common_sm
>>>> sysv,posix,mmap). In the
>>>> default case, sysv will never be queried/selected.
>>>> o Per some on-list discussion, now unlinking mmaped file in both
>>>> mmap
>>>> and posix
>>>> components (see: "System V Shared Memory for Open MPI:
>>>> Request for
>>>> Community
>>>> Input and Testing" thread).
>>>> o Assuming local process homogeneity with respect to all utilized
>>>> shared
>>>> memory facilities. That is, if one local process deems a
>>>> particular shared
>>>> memory facility acceptable, then ALL local processes should be
>>>> able to
>>>> utilize that facility. As it stands, this is an important
>>>> point
>>>> because one
>>>> process dictates to all other local processes which common sm
>>>> component will
>>>> be selected based on its own, local run-time test.
>>>> o Addressed some of George's code reuse concerns.
>>>>
>>>> If there are no major objections by August 17th, I'll commit the
>>>> code
>>>> after the
>>>> Tuesday morning conference call.
>>>>
>>>> Thanks!
>>>>
>>>> --
>>>> Samuel K. Gutierrez
>>>> Los Alamos National Laboratory
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> devel mailing list
>>>> devel_at_[hidden]
>>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>>>
>>>>
>>>> _______________________________________________
>>>> devel mailing list
>>>> devel_at_[hidden]
>>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>>>
>>>>
>>>> _______________________________________________
>>>> devel mailing list
>>>> devel_at_[hidden]
>>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> _______________________________________________
>>>> devel mailing list
>>>> devel_at_[hidden]
>>>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>>>
>>>
>>> --
>>> <mime-attachment.gif>
>>> Terry D. Dontje | Principal Software Engineer
>>> Developer Tools Engineering | +1.650.633.7054
>>> Oracle - Performance Technologies
>>> 95 Network Drive, Burlington, MA 01803
>>> Email terry.dontje_at_[hidden]
>>>
>>
>>
>> --
>> <mime-attachment.gif>
>> Terry D. Dontje | Principal Software Engineer
>> Developer Tools Engineering | +1.650.633.7054
>> Oracle - Performance Technologies
>> 95 Network Drive, Burlington, MA 01803
>> Email terry.dontje_at_[hidden]
>>
>> _______________________________________________
>> devel mailing list
>> devel_at_[hidden]
>> http://www.open-mpi.org/mailman/listinfo.cgi/devel
>
> _______________________________________________
> devel mailing list
> devel_at_[hidden]
> http://www.open-mpi.org/mailman/listinfo.cgi/devel
|
![[Flag]](../../../../../community/mirrors/flag-us.gif){kind=small}