However, no decision logic is changed by this commit so default behavior has not changed. This
is only selectable by runtime parameters.
This commit was SVN r18464.
used at nce (up to one unique collective module per collective function).
Matches r15795:15921 of the tmp/bwb-coll-select branch
This commit was SVN r15924.
The following SVN revisions from the original message are invalid or
inconsistent and therefore were not cross-referenced:
r15795
r15921
- adding linear algorithm with synchronization for gather.
This algorithm prevents congestion at root process, but introduces
synchronization (serializes non-root processes, but allows messages
to arrive from two processes at the same time).
It performed better than binomial and linear algorithms for large message,
and intermediate and large communicator sizes.
- Updating MPI_Gather decision function to reflect performance results
from MX. I will perform more measurements though - so this one can
change.
This commit was SVN r15165.
This "feature" is disabled by default and it should not affect the current performance.
In case when the message size is large and segment size is smaller than eager size for particular interface,
the leaf nodes in generalized reduce function can overflood parent nodes by sending all segments without
any synchronization. This can cause the parent to have HIGH number of unexpected messages (think 16MB
message with 1KB segments for example). In case of binomial algorithm root node always has at least one
child which is leaf, so this can potentially affect the root's performance significantly [Especially in
large communicators where root may have quite a few children (binomial tree for example)].
When the segment size is bigger than the eager size, rendezvous protocol ensures that this does
not happen so it is not necessary.
Originally, the problem was exposed in "infinite" bucket allocator clean up time for "small" segment sizes
(which may explain some "deadlocks" on Thunderbird tests).
To prevent this, we allow user to specify mca parameter "--mca coll_tuned_reduce_algorithm_max_requests NUM"
this limits number of outstanding messages from a leaf node in generalized reduce to the parent to NUM.
Messages are sent as non-blocking synchrnous messages, so syncronization happens at "wait" time.
The synchronization actually improved performance of pipeline and binomial algorithm for large message sizes
with 1KB segments over MX, but I need to test it some more to make sure it is consistent.
Since there is no easy way to find out what is "the eager" size for particular btl, I set the limit to 4000B.
If message/individual segment size is greater than 4000B - we will not use this feature. This variable may
or may not be exposed as mca parameter later...
I did not have any problems running it and both "default" and "synchronous" tests passed Intel Reduce* tests
up to 80 processes (over MX).
This commit was SVN r14518.
This merge adds Checkpoint/Restart support to Open MPI. The initial
frameworks and components support a LAM/MPI-like implementation.
This commit follows the risk assessment presented to the Open MPI core
development group on Feb. 22, 2007.
This commit closes trac:158
More details to follow.
This commit was SVN r14051.
The following SVN revisions from the original message are invalid or
inconsistent and therefore were not cross-referenced:
r13912
The following Trac tickets were found above:
Ticket 158 --> https://svn.open-mpi.org/trac/ompi/ticket/158
Currently 3 algorithms are available:
- non-overlapping, reduce + scatterv, (works for non-commutative operations)
- recursive halving algorithm (copied from basic module)
- ring algorithm (similar to allreduce ring, for large messages)
This commit was SVN r13929.
Algorithm allows user to specify the segment size to be used for computation/communication overlap.
The additional memory requirement for the algorithm is 2 x segment size.
It performed well for (really) large message sizes over MX and it passed intel Allreduce_c and Allreduce_loc_c tests.
This commit was SVN r13832.
- the block sizes are computed in more uniformn way.
The first k blocks may be 1 element larger than the remaining blocks.
The algorithm passed Intel Allreduce_c and Allreduce_loc_c tests, and
IMB-3.2 Allreduce, over TCP and both btl and mtl MX (up to 128 processes).
The algorithm still only supports commutative operations.
This commit was SVN r13738.
outstanding requests can be limited using mca parameters.
The implementation passed Intel, IMB-3.2, and mpi_test_suite tests over
TCP and MX up to 128 processes (64 nodes), on both 32-bit and 64-bit machines.
It is not activated by default, but it should be useful for really large
communicator sizes.
This commit was SVN r13720.
Implementation passed intel: MPI_Reduce_c , MPI_Reduce_loc_c, and MPI_Reduce_user_c tests
over TCP, BTL MX, and MTL MX, as well as, mpi_test_suite Reduce tests (up to 64 nodes).
The algorithm is still not activated by decision function (will be in the near future).
This commit was SVN r13657.
- Allreduce algorithms:
- Recursive doubling is used for small messages (up to 10KB) and can be used for
both commutative and non-commutative operations.
Recursive doubling passed OCC, IMB-3.2, Intel (Allreduce_c, Allreduce_loc_c, and
Allreduce_user_c), mpi_test_suite (Allreduce MIN/MAX, and Allreduce MIN/MAX with
MPI_IN_PLACE) tests on TCP up to 36 nodes and MX up to 64 nodes.
- Ring algorithms performs well for larger messages but cannot be used for
non-commutative operations. It passed the same tests as recursive doubling, except
some of the non-commutative tests in Intel benchmarks Allreduce_loc_c and Allreduce_user_c
(which was expected).
- MPI_Allreduce with new decision function passed all of the tests mentioned above.
- Cleaning up coll_tuned_util. Moving isendrecv to static inline just like sendrecv.
This commit was SVN r13252.
It contains four algorithms:
Bruck (ciel(logP) steps), Recursive Doubling (log(P) for power-of-2 processes), Ring (P-1 steps),
and Neighbor Exchange (P/2 steps for even number of processes).
All algorithms passed occ, IMB-2.3, and intel verification tests from ompi-tests/ for up to 56 processes.
The fixed decision function is based on results collected over MX on the Grig cluster at
the University of Tennessee at Knoxville.
I have also added (and commented out) copy of MPICH2 decision function for allgather
(from their IJHPCA 2005 paper).
This commit was SVN r12910.
- consistent arguments checking (not allowing to select an algorithm which
is not available)
- consistent way of computing the segcount (number of datatypes by segment).
- small cleanups.
- more informative debugging messages.
This commit was SVN r12545.
description. Most of the bcast algorithms can be completed using this
generic function once we create the tree structure. Add all kind of
trees.
There are 2 versions of the generic bcast function. One using overlapping
between receives (for intermediary nodes) and then blocking sends to all
childs and another where all sends are non blocking. I still have to
figure out which one give the smallest overhead.
This commit was SVN r12530.
the default decision functions (for broadcast, reduce and barrier) are based on a
high performance network (not TCP). It should give good performance (really good) for
any network having the following caracteristics: small latency (5 microseconds) and good
bandwidth (more than 1Gb/s).
+ Cleanup of the reduce algorithms, plus 2 new algorithms (binary and binomial). Now most
of the reduce algorithms use a generic tree based function for completing the reduce.
+ Added macros for computing the trees (they are used for bcast and reduce right now).
+ Allow the usage of all 5 topologies.
+ Jelena's implementation of a binary tree that can be used for non commutative operations.
Right now only the tree building function is there, it will get activated soon.
+ Some others minor cleanups.
This commit was SVN r12326.
different macros, one for each project. Therefore, now we have OPAL_DECLSPEC,
ORTE_DECLSPEC and OMPI_DECLSPEC. Please use them based on the sub-project.
This commit was SVN r11270.
(1) As pointed out by Torsten after Jeff comment that there are 15 collectives yesterday.. nope.. I have 16 but
miss counted them in my ifdefs (I had two #11s). Replaces with enum...
(2) Added a readonly MCA param for how many backend algorithms are available per collective (used by benchmarker/STS)
This allowed me to remove the tuned query internal functions and replace them with ompi_coll_tuned_forced_max_algorithms[COLL].
(3) I was reading the user forced MCA params for the collectives on each comm create (module init) but I then put the
values into a global set of variables (like ompi_coll_tuned_reduce_forced_algorithm).
To fix this and make the code neater:
(a) The component looks up the MCA param indices on Open if dynamic_rules is set via the
ompi_coll_tuned_COLLECTIVE_intra_check_forced_init () call.
(b) Got rid of the ompi_coll_ompi_coll_tuned_COLLECTIVE_forced_algorithm/segmentsize/etc globals with a struct that
is now cached on the module data hung off the communicator. i.e. done right.
(c) On module init if dynamic rules enabled we call a general getvalues routine (in coll_tuned_forced.c) to get the
CURRENT values using the MCA param indices and then put them on the modules data segment.
A shorter version of getvalues exists for barrier which only needs the algorithm choice
This commit was SVN r9663.
- move files out of toplevel include/ and etc/, moving it into the
sub-projects
- rather than including config headers with <project>/include,
have them as <project>
- require all headers to be included with a project prefix, with
the exception of the config headers ({opal,orte,ompi}_config.h
mpi.h, and mpif.h)
This commit was SVN r8985.
(apparently we've been doing this in opal and orte, but not in ompi
yet). All public symbols begin with "ompi_coll_tuned_" (not
mca_coll_tuned_) except the component struct. Now this component
passes the illegal symbol report with no hits.
This commit was SVN r8589.
Lots of misc fixes: printfs->opal_output, handles fanin/out correctly for forced ops
unused vars, correct calculations on meaning of 'msgsize' for decision functions
(varies depending on algorithm), etc
This commit was SVN r8113.
started to add static (fixed if) statement based decision rules based on gigE numbers
added mca params so that a user can force a certain algorithm/segment/topo on a per collective basis
(this is not in the fixed call path but only in the dynamic (at com create) call path).
(these params can be used by test suites such as OCC to choice which algorithm they are using).
This commit was SVN r7854.
-added some alltoall calls (pairwise checked ok, bruck testing)
-changes in use of data hung of communicator
-making sendrecv call a true inline function
-more use ompi_ddt routines
This commit was SVN r7337.
Changed component so choice of decision functions controlled by mca params
(for now fixed decision functions (if statements) default)
started fixes for the various bcasts
This commit was SVN r7117.
