| msg187192 - (view) |
Author: Antoine Pitrou (pitrou) *  |
Date: 2013-04-17 18:40 |
| Ubuntu's system Python 3.3 shows consistently better performance than a vanilla Python 3.3: around 10-15% faster in general (see attached benchmark numbers). If this can be attributed to different compilation options, it would be nice to backport those options to our standard build config. |
|
|
| msg187193 - (view) |
Author: Matthias Klose (doko) * |
Date: 2013-04-17 18:45 |
| most of that can be attributed to the pgo build, which is upstream for a long time. the second thing to do is to build with lto, and see what speedups you get in addition. and it certainly helps to build the interpreter statically (without --enable-shared). but thanks to confirming my own experience ;) |
|
|
| msg187245 - (view) |
Author: Christian Heimes (christian.heimes) * |
Date: 2013-04-18 13:05 |
| Here is a patch for -flto. You need to run autoconf to re-generate configure, too. |
|
|
| msg187246 - (view) |
Author: Matthias Klose (doko) * |
Date: 2013-04-18 13:24 |
| the proposed patch is wrong. when linking with -flto, you should pass all the relevant CFLAGS to the linker as well. Also pass -fuse-linker-plugin. and this should be an opt-in, not the default. Depending on the architecture and the compiler version, -flto is not as stable as you want it to be. and last, this ends up as the default for building third party extensions too, which again, I think should be an opt-in. |
|
|
| msg248993 - (view) |
Author: Stefan Behnel (scoder) * |
Date: 2015-08-22 19:27 |
| Issue 24915 suggests PGO and comes with an actual patch. I suggest rejecting this ticket as too broad. |
|
|
| msg248994 - (view) |
Author: Antoine Pitrou (pitrou) * |
Date: 2015-08-22 19:29 |
| LTO (Link-Time Optimization) is not the same as PGO, though I guess it can take advantage of PGO for its heuristics. |
|
|
| msg249103 - (view) |
Author: Raymond Hettinger (rhettinger) * |
Date: 2015-08-25 03:00 |
| I would like the see LTO enabled. The intermodule calls to code in abstract.c would become less expensive. |
|
|
| msg249253 - (view) |
Author: Antoine Pitrou (pitrou) * |
Date: 2015-08-27 19:08 |
| Note this patch is likely wrong, as it doesn't add the optimization options to the linker invocation. According to the gcc does, """To use the link-time optimizer, -flto and optimization options should be specified at compile time and during the final link""". So probably OPTshouldbeaddedtoOPT should be added to OPTshouldbeaddedtoPY_LDFLAGS. |
|
|
| msg249260 - (view) |
Author: Antoine Pitrou (pitrou) * |
Date: 2015-08-27 21:09 |
| For the record, the gain for LTO+PGO (with "-flto -O3") over PGO alone seems to be between 0% and 10% for most benchmarks. |
|
|
| msg249261 - (view) |
Author: Antoine Pitrou (pitrou) * |
Date: 2015-08-27 21:10 |
| You can test for yourself by passing `CFLAGS="-flto -O3" LDFLAGS="-flto -O3"` to ./configure (using gcc). |
|
|
| msg251304 - (view) |
Author: STINNER Victor (vstinner) * |
Date: 2015-09-22 10:28 |
| > For the record, the gain for LTO+PGO (with "-flto -O3") over PGO alone seems to be between 0% and 10% for most benchmarks. Hum, does it make sense to enable LTO without PGO? |
|
|
| msg251305 - (view) |
Author: Antoine Pitrou (pitrou) * |
Date: 2015-09-22 10:31 |
| > Hum, does it make sense to enable LTO without PGO? Probably not. By the way, I now have a small ARM system to play with, and there the gain of LTO+PGO over PGO alone is around 10%. Also note LTO can make compilation times much longer (it's the linking step actually, which can take minutes). |
|
|
| msg251335 - (view) |
Author: Matthias Klose (doko) * |
Date: 2015-09-22 17:44 |
| On 22.09.2015 12:31, Antoine Pitrou wrote: > Also note LTO can make compilation times much longer (it's the linking step actually, which can take minutes). use -flto=jobserver |
|
|
| msg251608 - (view) |
Author: Terry J. Reedy (terry.reedy) * |
Date: 2015-09-25 20:26 |
| #24915 is about adding pgo and has a slew of patches. |
|
|
| msg256281 - (view) |
Author: Alecsandru Patrascu (alecsandru.patrascu) * |
Date: 2015-12-12 12:05 |
| Hi, I added a dedicated issue just for LTO only when using GCC and CLANG (http://bugs.python.org/issue25702), that works well with PGO also. |
|
|
| msg258629 - (view) |
Author: Zachary Ware (zach.ware) * |
Date: 2016-01-19 22:37 |
| PGO is available as `make profile-opt`, LTO has a patch in . Are there any other interesting options worth investigating? |
|
|
| msg324898 - (view) |
Author: Zachary Ware (zach.ware) * |
Date: 2018-09-09 19:05 |
| After 2.5 years without response, I think the answer is probably "no" :) |
|
|