Kristján Valur Jónsson <krist...@ccpgames.com> added the comment: I looked at ccbench. It's a great tool. I've added two features to it (see the attached patch) -y option to turn off the "do_yield" option in throughput, and so measure thread scheduling without assistance, and the throughput option now also computes "balance", which is the standard deviation of the throughput of each thread normalized by the average.
I give you three results for throughput, to demonstrate the ROUNDROBIN_GIL implementation: 1) LEGACY_GIL, no forced switching C:\pydev\python\trunk\PCbuild>python.exe ..\Tools\ccbench\ccbench.py -y -t == CPython 2.7a4+.0 (trunk) == == AMD64 Windows on 'Intel64 Family 6 Model 23 Stepping 6, GenuineIntel' == --- Throughput --- Pi calculation (Python) threads= 1: 672 iterations/s. balance threads= 2: 597 ( 88%) 0.4243 threads= 3: 603 ( 89%) 0.2475 threads= 4: 596 ( 88%) 0.4776 regular expression (C) threads= 1: 571 iterations/s. balance threads= 2: 565 ( 98%) 0.6203 threads= 3: 567 ( 99%) 1.6867 threads= 4: 570 ( 99%) 1.1670 SHA1 hashing (C) threads= 1: 1269 iterations/s. balance threads= 2: 1268 ( 99%) 1.1470 threads= 3: 1270 (100%) 0.6024 threads= 4: 1263 ( 99%) 0.7419 LEGACY_GIL, with forced switching C:\pydev\python\trunk\PCbuild>python.exe ..\Tools\ccbench\ccbench.py -t == CPython 2.7a4+.0 (trunk) == == AMD64 Windows on 'Intel64 Family 6 Model 23 Stepping 6, GenuineIntel' == --- Throughput --- Pi calculation (Python) threads= 1: 663 iterations/s. balance threads= 2: 605 ( 91%) 0.0232 threads= 3: 599 ( 90%) 0.1988 threads= 4: 601 ( 90%) 0.4648 regular expression (C) threads= 1: 568 iterations/s. balance threads= 2: 562 ( 99%) 0.1737 threads= 3: 571 (100%) 0.3950 threads= 4: 566 ( 99%) 0.3158 SHA1 hashing (C) threads= 1: 1275 iterations/s. balance threads= 2: 1267 ( 99%) 0.7238 threads= 3: 1271 ( 99%) 0.2405 threads= 4: 1270 ( 99%) 0.1508 Using the forced "do_yield" helps balance things, but not much. We still have a .7 balance in SHA1 hashing for two threads. Now, for ROUNDROBIN_GIL, and no forced switching: C:\pydev\python\trunk\PCbuild>python.exe ..\Tools\ccbench\ccbench.py -t -y == CPython 2.7a4+.0 (trunk) == == AMD64 Windows on 'Intel64 Family 6 Model 23 Stepping 6, GenuineIntel' == --- Throughput --- Pi calculation (Python) threads= 1: 672 iterations/s. balance threads= 2: 485 ( 72%) 0.0289 threads= 3: 448 ( 66%) 0.0737 threads= 4: 476 ( 70%) 0.0408 regular expression (C) threads= 1: 569 iterations/s. balance threads= 2: 551 ( 96%) 0.0505 threads= 3: 551 ( 96%) 0.1637 threads= 4: 551 ( 96%) 0.2020 SHA1 hashing (C) threads= 1: 1271 iterations/s. balance threads= 2: 1262 ( 99%) 0.0111 threads= 3: 1207 ( 94%) 0.0143 threads= 4: 1202 ( 94%) 0.0317 Notice the much better balance value, and this is without the forced sleep. Also note a lower througput when computing pi with threads. This is because yielding every 100 opcodes now actually works, and the aforementioned instruction cache problem kicks in. Increasing the checkinterval to 1000 solves this: C:\pydev\python\trunk\PCbuild>python.exe ..\Tools\ccbench\ccbench.py -t -y -i100 0 == CPython 2.7a4+.0 (trunk) == == AMD64 Windows on 'Intel64 Family 6 Model 23 Stepping 6, GenuineIntel' == --- Throughput --- Pi calculation (Python) threads= 1: 673 iterations/s. balance threads= 2: 628 ( 93%) 0.0000 threads= 3: 603 ( 89%) 0.0284 threads= 4: 606 ( 90%) 0.0328 regular expression (C) threads= 1: 570 iterations/s. balance threads= 2: 569 ( 99%) 0.2729 threads= 3: 562 ( 98%) 0.6595 threads= 4: 560 ( 98%) 1.2440 SHA1 hashing (C) threads= 1: 1265 iterations/s. balance threads= 2: 1256 ( 99%) 0.0000 threads= 3: 1264 ( 99%) 0.0759 threads= 4: 1255 ( 99%) 0.1309 If no one objects, I'd like to submit this changed ccbench.py to the trunk. ---------- Added file: http://bugs.python.org/file16867/ccbench.patch _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue8299> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: http://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
