Andrew Trick 192311ab9a MI-Sched: handle latency of in-order operations with the new machine model.
The per-operand machine model allows the target to define "unbuffered"
processor resources. This change is a quick, cheap way to model stalls
caused by the latency of operations that use such resources. This only
applies when the processor's micro-op buffer size is non-zero
(Out-of-Order). We can't precisely model in-order stalls during
out-of-order execution, but this is an easy and effective
heuristic. It benefits cortex-a9 scheduling when using the new
machine model, which is not yet on by default.

MI-Sched for armv7 was evaluated on Swift (and only not enabled because
of a performance bug related to predication). However, we never
evaluated Cortex-A9 performance on MI-Sched in its current form. This
change adds MI-Sched functionality to reach performance goals on
A9. The only remaining change is to allow MI-Sched to run as a PostRA
pass.

I evaluated performance using a set of options to estimate the performance impact once MI sched is default on armv7:
-mcpu=cortex-a9 -disable-post-ra -misched-bench -scheditins=false

For a simple saxpy loop I see a 1.7x speedup. Here are the llvm-testsuite results:
(min run time over 2 runs, filtering tiny changes)

Speedups:
| Benchmarks/BenchmarkGame/recursive         |  52.39% |
| Benchmarks/VersaBench/beamformer           |  20.80% |
| Benchmarks/Misc/pi                         |  19.97% |
| Benchmarks/Misc/mandel-2                   |  19.95% |
| SPEC/CFP2000/188.ammp                      |  18.72% |
| Benchmarks/McCat/08-main/main              |  18.58% |
| Benchmarks/Misc-C++/Large/sphereflake      |  18.46% |
| Benchmarks/Olden/power                     |  17.11% |
| Benchmarks/Misc-C++/mandel-text            |  16.47% |
| Benchmarks/Misc/oourafft                   |  15.94% |
| Benchmarks/Misc/flops-7                    |  14.99% |
| Benchmarks/FreeBench/distray               |  14.26% |
| SPEC/CFP2006/470.lbm                       |  14.00% |
| mediabench/mpeg2/mpeg2dec/mpeg2decode      |  12.28% |
| Benchmarks/SmallPT/smallpt                 |  10.36% |
| Benchmarks/Misc-C++/Large/ray              |   8.97% |
| Benchmarks/Misc/fp-convert                 |   8.75% |
| Benchmarks/Olden/perimeter                 |   7.10% |
| Benchmarks/Bullet/bullet                   |   7.03% |
| Benchmarks/Misc/mandel                     |   6.75% |
| Benchmarks/Olden/voronoi                   |   6.26% |
| Benchmarks/Misc/flops-8                    |   5.77% |
| Benchmarks/Misc/matmul_f64_4x4             |   5.19% |
| Benchmarks/MiBench/security-rijndael       |   5.15% |
| Benchmarks/Misc/flops-6                    |   5.10% |
| Benchmarks/Olden/tsp                       |   4.46% |
| Benchmarks/MiBench/consumer-lame           |   4.28% |
| Benchmarks/Misc/flops-5                    |   4.27% |
| Benchmarks/mafft/pairlocalalign            |   4.19% |
| Benchmarks/Misc/himenobmtxpa               |   4.07% |
| Benchmarks/Misc/lowercase                  |   4.06% |
| SPEC/CFP2006/433.milc                      |   3.99% |
| Benchmarks/tramp3d-v4                      |   3.79% |
| Benchmarks/FreeBench/pifft                 |   3.66% |
| Benchmarks/Ptrdist/ks                      |   3.21% |
| Benchmarks/Adobe-C++/loop_unroll           |   3.12% |
| SPEC/CINT2000/175.vpr                      |   3.12% |
| Benchmarks/nbench                          |   2.98% |
| SPEC/CFP2000/183.equake                    |   2.91% |
| Benchmarks/Misc/perlin                     |   2.85% |
| Benchmarks/Misc/flops-1                    |   2.82% |
| Benchmarks/Misc-C++-EH/spirit              |   2.80% |
| Benchmarks/Misc/flops-2                    |   2.77% |
| Benchmarks/NPB-serial/is                   |   2.42% |
| Benchmarks/ASC_Sequoia/CrystalMk           |   2.33% |
| Benchmarks/BenchmarkGame/n-body            |   2.28% |
| Benchmarks/SciMark2-C/scimark2             |   2.27% |
| Benchmarks/Olden/bh                        |   2.03% |
| skidmarks10/skidmarks                      |   1.81% |
| Benchmarks/Misc/flops                      |   1.72% |

Slowdowns:
| Benchmarks/llubenchmark/llu                | -14.14% |
| Benchmarks/Polybench/stencils/seidel-2d    |  -5.67% |
| Benchmarks/Adobe-C++/functionobjects       |  -5.25% |
| Benchmarks/Misc-C++/oopack_v1p8            |  -5.00% |
| Benchmarks/Shootout/hash                   |  -2.35% |
| Benchmarks/Prolangs-C++/ocean              |  -2.01% |
| Benchmarks/Polybench/medley/floyd-warshall |  -1.98% |
| Polybench/linear-algebra/kernels/3mm       |  -1.95% |
| Benchmarks/McCat/09-vor/vor                |  -1.68% |

llvm-svn: 196516
2013-12-05 17:55:58 +00:00
2013-12-05 05:44:44 +00:00
2013-12-05 05:44:44 +00:00
2013-12-05 05:44:44 +00:00
2012-10-09 23:48:34 +00:00
2013-12-04 09:42:49 +00:00
2013-11-20 10:10:50 +00:00
2013-11-17 11:44:36 +00:00

Low Level Virtual Machine (LLVM)
================================

This directory and its subdirectories contain source code for the Low Level
Virtual Machine, a toolkit for the construction of highly optimized compilers,
optimizers, and runtime environments.

LLVM is open source software. You may freely distribute it under the terms of
the license agreement found in LICENSE.txt.

Please see the documentation provided in docs/ for further
assistance with LLVM, and in particular docs/GettingStarted.rst for getting
started with LLVM and docs/README.txt for an overview of LLVM's
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If you're writing a package for LLVM, see docs/Packaging.rst for our
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