Hi all,
Thank you for your reply...
My problem is i want to *reduce library* size by removing unwanted plugin's.
Here *libmpi.so.12.0.3 *size is 2.4MB.
How can i know what are the* pluggin's *included to* build the*
*libmpi.so.12.0.3* and how can remove.
Thanks&Regards,
Mahesh N
On Tue, Nov 1, 2016 at 11:43 AM, Mahesh Nanavalla <
mahesh.nanavalla...@gmail.com> wrote:
> Hi Jeff Squyres,
>
> Thank you for your reply...
>
> My problem is i want to *reduce library* size by removing unwanted
> plugin's.
>
> Here *libmpi.so.12.0.3 *size is 2.4MB.
>
> How can i know what are the* pluggin's *included to* build the*
> *libmpi.so.12.0.3* and how can remove.
>
> Thanks&Regards,
> Mahesh N
>
> On Fri, Oct 28, 2016 at 7:09 PM, Jeff Squyres (jsquyres) <
> jsquy...@cisco.com> wrote:
>
>> On Oct 28, 2016, at 8:12 AM, Mahesh Nanavalla <
>> mahesh.nanavalla...@gmail.com> wrote:
>> >
>> > i have configured as below for arm
>> >
>> > ./configure --enable-orterun-prefix-by-default
>> --prefix="/home/nmahesh/Workspace/ARM_MPI/openmpi"
>> CC=arm-openwrt-linux-muslgnueabi-gcc CXX=arm-openwrt-linux-muslgnueabi-g++
>> --host=arm-openwrt-linux-muslgnueabi --enable-script-wrapper-compilers
>> --disable-mpi-fortran --enable-dlopen --enable-shared --disable-vt
>> --disable-java --disable-libompitrace --disable-static
>>
>> Note that there is a tradeoff here: --enable-dlopen will reduce the size
>> of libmpi.so by splitting out all the plugins into separate DSOs (dynamic
>> shared objects -- i.e., individual .so plugin files). But note that some
>> of plugins are quite small in terms of code. I mention this because when
>> you dlopen a DSO, it will load in DSOs in units of pages. So even if a DSO
>> only has 1KB of code, it will use <page_size> of bytes in your running
>> process (e.g., 4KB -- or whatever the page size is on your system).
>>
>> On the other hand, if you --disable-dlopen, then all of Open MPI's
>> plugins are slurped into libmpi.so (and friends). Meaning: no DSOs, no
>> dlopen, no page-boundary-loading behavior. This allows the compiler/linker
>> to pack in all the plugins into memory more efficiently (because they'll be
>> compiled as part of libmpi.so, and all the code is packed in there -- just
>> like any other library). Your total memory usage in the process may be
>> smaller.
>>
>> Sidenote: if you run more than one MPI process per node, then libmpi.so
>> (and friends) will be shared between processes. You're assumedly running
>> in an embedded environment, so I don't know if this factor matters (i.e., I
>> don't know if you'll run with ppn>1), but I thought I'd mention it anyway.
>>
>> On the other hand (that's your third hand, for those at home
>> counting...), you may not want to include *all* the plugins. I.e., there
>> may be a bunch of plugins that you're not actually using, and therefore if
>> they are compiled in as part of libmpi.so (and friends), they're consuming
>> space that you don't want/need. So the dlopen mechanism might actually be
>> better -- because Open MPI may dlopen a plugin at run time, determine that
>> it won't be used, and then dlclose it (i.e., release the memory that would
>> have been used for it).
>>
>> On the other (fourth!) hand, you can actually tell Open MPI to *not*
>> build specific plugins with the --enable-dso-no-build=LIST configure
>> option. I.e., if you know exactly what plugins you want to use, you can
>> negate the ones that you *don't* want to use on the configure line, use
>> --disable-static and --disable-dlopen, and you'll likely use the least
>> amount of memory. This is admittedly a bit clunky, but Open MPI's
>> configure process was (obviously) not optimized for this use case -- it's
>> much more optimized to the "build everything possible, and figure out which
>> to use at run time" use case.
>>
>> If you really want to hit rock bottom on MPI process size in your
>> embedded environment, you can do some experimentation to figure out exactly
>> which components you need. You can use repeated runs with "mpirun --mca
>> ABC_base_verbose 100 ...", where "ABC" is each of Open MPI's framework
>> names ("framework" = collection of plugins of the same type). This verbose
>> output will show you exactly which components are opened, which ones are
>> used, and which ones are discarded. You can build up a list of all the
>> discarded components and --enable-mca-no-build them.
>>
>> > While i am running the using mpirun
>> > am getting following errror..
>> > root@OpenWrt:~# /usr/bin/mpirun --allow-run-as-root -np 1
>> /usr/bin/openmpiWiFiBulb
>> > ------------------------------------------------------------
>> --------------
>> > Sorry! You were supposed to get help about:
>> > opal_init:startup:internal-failure
>> > But I couldn't open the help file:
>> >
>> > /home/nmahesh/Workspace/ARM_MPI/openmpi/share/openmpi/help-opal-runtime.txt:
>> No such file or directory. Sorry!
>>
>> So this is really two errors:
>>
>> 1. The help message file is not being found.
>> 2. Something is obviously going wrong during opal_init() (which is one of
>> Open MPI's startup functions).
>>
>> For #1, when I do a default build of Open MPI 1.10.3, that file *is*
>> installed. Are you trimming the installation tree, perchance? If so, if
>> you can put at least that one file back in its installation location (it's
>> in the Open MPI source tarball), it might reveal more information on
>> exactly what is failing.
>>
>> Additionally, I wonder if shared memory is not getting setup right. Try
>> running with "mpirun --mca shmem_base_verbose 100 ..." and see if it's
>> reporting an error.
>>
>> --
>> Jeff Squyres
>> jsquy...@cisco.com
>> For corporate legal information go to: http://www.cisco.com/web/about
>> /doing_business/legal/cri/
>>
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>>
>
>
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