This has shown better results for 2mm, 3mm and a couple of other benchmarks.
After this we show consistenly better results as PoCC with maxfuse. We need
to see if PoCC can also give better results with another fusion strategy.
llvm-svn: 149267
maximise_band_depth does not seem to have any effect for now, but it may help to
increase the amount of tileable loops. We expose the flag to be able to analyze
its effects when looking into individual benchmarks.
llvm-svn: 149266
This speeds up the scheduler by orders of magnitude and in addition yields often
to a better schedule.
With this we can compile all polybench kernels with less than 5x compile time
overhead. In general the overhead is even less than 2-3x. This is still with
running a lot of redundant passes and no compile time tuning at all. There are
several obvious areas where we can improve here further.
There are also two test cases where we cannot find a schedule any more (cholesky
and another). I will look into them later on.
With this we have a very solid base line from which we can start to optimize
further.
llvm-svn: 149263
Previously the scheduler was splitting bands at the level at which it detected
that the splitting of the band is necessary. This may introduce an additional
level of bands, that can be avoided by backtracking and splitting on a higher
level. Additional splits reduce the number of loops that can be tiled, such that
avoiding splits and maximizing the band depth seems preferable.
As a first data point we looked at 2mm and 3mm from the polybench test suite.
For both maximizing the tilable bands results in a significant (5-10x)
performance improvement.
This patch enables the isl scheduler option to maximize the band depth.
llvm-svn: 146557
If larger coefficients appear as part of the input dependences, the schedule
calculation can take a very long time. We observed that the main overhead in
this calculation is due to optimizing the constant coefficients. They are
misused to increase locality by merging several unrelated dimensions into a
single dimension. This unwanted optimization increases the complexity of the
generated code and furthermore slows it down.
We use a new isl scheduler option to bound the values in the constant dimension
by a user defined value (20 in our case). If the right value is choosen, costly
overoptimization is prevented.
This solution works, but requires a specific (here almost randomly choosen)
value by which the constants are bound. For the moment, this is our best
solution, but we hope to to find a more generic one later on.
After these patch the extremly long compile time for simple kernels like 2mm or
3mm is reduced to a reasonable amount of time (Not more than a couple of seconds
even in debug mode).
llvm-svn: 146556
- Use uppercase letters according to the LLVM coding style
- Rename functions to not include 'tiledSchedule', but just Schedule. This
is more correct as tiling might be disabled.
llvm-svn: 144899
Polly should now be compiled with CLooG 0c252c88946b27b7b61a1a8d8fd7f94d2461dbfd
and isl 56b7d238929980e62218525b4b3be121af386edf. The most convenient way to
update is utils/checkout_cloog.sh.
llvm-svn: 141251
Due to the recent introduction of isl_id, parameters need now always to be
aligned. This was not yet taken care of in the code path of vectorization and
dependence analysis.
llvm-svn: 138555
We just strip-mine the innermost dimension by the vector width. This does not
take into account if this dimension is parallel nor if it is constant.
llvm-svn: 134186
isl introduced a new representation for the schedules it calculates. The new
representation uses a forest of bands and is closer to the structure of the
data as the old interface. Switch to the new interface, as it is nicer to use
and as the old interface will soon be removed from isl.
WARNING: This commit needs a version of isl that is more recent that the one
included in CLooG. See:
http://polly.grosser.es/get_started.html#islTrunk
llvm-svn: 134181
The isl based routines implement a new interpretation of the Pluto algorithm
new interpretation. This patch requires a recent version of isl to be installed.
llvm-svn: 131354
Tobias Grosser