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| author | Raymond Hettinger <python@rcn.com> | 2013-08-19 16:12:20 (GMT) |
|---|---|---|
| committer | Raymond Hettinger <python@rcn.com> | 2013-08-19 16:12:20 (GMT) |
| commit | c301b55d7bf667b690065e19c883d9c02accb8bb (patch) | |
| tree | 52760853a7df1e9d7158c4b27d931cce8f7acf16 | |
| parent | 85532eb2122bf32a90c6c26983d843b8223df37b (diff) | |
| download | cpython-c301b55d7bf667b690065e19c883d9c02accb8bb.zip cpython-c301b55d7bf667b690065e19c883d9c02accb8bb.tar.gz cpython-c301b55d7bf667b690065e19c883d9c02accb8bb.tar.bz2 | |
Issue 18774: Update news and whatsnew for the set optimizations
| -rw-r--r-- | Doc/whatsnew/3.4.rst | 6 | ||||
| -rw-r--r-- | Misc/NEWS | 4 |
2 files changed, 10 insertions, 0 deletions
diff --git a/Doc/whatsnew/3.4.rst b/Doc/whatsnew/3.4.rst index 1c30d43..f7d0c26 100644 --- a/Doc/whatsnew/3.4.rst +++ b/Doc/whatsnew/3.4.rst @@ -389,6 +389,12 @@ Major performance enhancements have been added: * The UTF-32 decoder is now 3x to 4x faster. +* The cost of hash collisions for sets is now reduced. Each hash table + probe now checks a second key/hash pair for each cache line retrieved. + This exploits cache locality to make collision resolution less expensive. + + (Contributed by Raymond Hetting in :issue"`18771`.) + Build and C API Changes ======================= @@ -12,6 +12,10 @@ Core and Builtins - Issue #18774: Remove last bits of GNU PTH thread code and thread_pth.h. +- Issue #18771: Add optimization to set object lookups to reduce the cost + of hash collisions. The core idea is to inspect a second key/hash pair + for each cache line retrieved. + - Issue #16105: When a signal handler fails to write to the file descriptor registered with ``signal.set_wakeup_fd()``, report an exception instead of ignoring the error. |