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Created on 2013-09-01 05:14 by rhettinger, last changed 2022-04-11 14:57 by admin. This issue is now closed.
| Files | ||||
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| File name | Uploaded | Description | Edit | |
| noincref.diff | rhettinger, 2013-09-05 08:15 | First draft to eliminate incref/decref on dummy objects | review | |
| Messages (6) | |||
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| msg196706 - (view) | Author: Raymond Hettinger (rhettinger) *  |
Date: 2013-09-01 05:14 | |
Once http://bugs.python.org/issue18835 is resolved, I would like to see the various set optimizations applied to dictionaries as well: * Move the key before the hash in the dict struct (the key is accessed more frequently in the code and being in the first struct position allows it to be looked-up without a struct offset). * Don't INCREF and DECREF dummy objects. Only one reference needs to be held. See http://bugs.python.org/issue18797 * Reduce the cost of hash collisions by inspecting nearby dict entries for matches prior to moving on to other probes elsewhere in memory. See http://bugs.python.org/issue18771 * Make the previous improvement more effective by using aligned memory allocations for the dict tables. See http://bugs.python.org/issue18835 Collectively, these optimizations can substantially improve dictionary performance. |
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| msg196710 - (view) | Author: Eric Snow (eric.snow) * |
Date: 2013-09-01 05:39 | |
+1 This is worth trying. |
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| msg196909 - (view) | Author: Eli Bendersky (eli.bendersky) * |
Date: 2013-09-04 13:24 | |
I'm still interested in seeing benchmarks that show where this actually improves things and by how much. Also, whether any regressions occur and how serious they are. |
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| msg234881 - (view) | Author: Serhiy Storchaka (serhiy.storchaka) * |
Date: 2015-01-28 10:14 | |
noincref.diff doesn't contain all necessary changes. For example dummy is increfed in dict_pop() and dict_popitem() and may be decrefed at insert. As in sets we can got rid of few comparisons with dummy if set dummy hashes to -1. |
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| msg239382 - (view) | Author: STINNER Victor (vstinner) * |
Date: 2015-03-27 08:54 | |
Hi, what's the status of this issue? Is anyone working one it? |
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| msg258944 - (view) | Author: Raymond Hettinger (rhettinger) * |
Date: 2016-01-26 03:38 | |
> Hi, what's the status of this issue? Is anyone working one it? In the present environment, I feel like advancing this work would be an uphill battle and that much of my time investment would be wasted unnecessarily. That's too bad, because significant r&d time has already been invested and it has had nice payoffs with set objects. |
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| History | |||
|---|---|---|---|
| Date | User | Action | Args |
| 2022-04-11 14:57:50 | admin | set | github: 63098 |
| 2016-01-26 03:38:40 | rhettinger | set | status: open -> closed messages: + msg258944 |
| 2015-03-27 08:54:17 | vstinner | set | messages: + msg239382 |
| 2015-01-28 10:14:02 | serhiy.storchaka | set | messages: + msg234881 |
| 2015-01-20 08:11:10 | rhettinger | set | versions: + Python 3.5, - Python 3.4 |
| 2013-09-05 08:15:00 | rhettinger | set | files:
+ noincref.diff keywords: + patch |
| 2013-09-04 13:38:19 | pitrou | set | nosy:
+ serhiy.storchaka |
| 2013-09-04 13:24:21 | eli.bendersky | set | nosy:
+ eli.bendersky messages: + msg196909 |
| 2013-09-04 00:49:05 | Alan.Cristhian | set | nosy:
+ Alan.Cristhian |
| 2013-09-01 05:39:38 | eric.snow | set | nosy:
+ Mark.Shannon, eric.snow messages: + msg196710 |
| 2013-09-01 05:14:53 | rhettinger | create | |