Mercurial > hg
view mercurial/bitmanipulation.h @ 35599:af25237be091
perf: add threading capability to perfbdiff
Since we are releasing the GIL during diffing, it is interesting to see how a
thread pool would perform on diffing. We add a new `--threads` argument to
commands. Synchronizing the thread pool is a bit complex because we want to be
able to reuse it from one run to another.
On my computer (i7 with 4 cores + hyperthreading), I get the following data for
about 12000 revisions:
threads wall comb wall gain comb overhead
none 31.596715 31.59 0.00% 0.00%
1 31.621228 31.62 -0.08% 0.09%
2 16.406202 32.8 48.08% 3.83%
3 11.598334 34.76 63.29% 10.03%
4 9.205421 36.77 70.87% 16.40%
5 8.517604 42.51 73.04% 34.57%
6 7.94645 47.58 74.85% 50.62%
7 7.434972 51.92 76.47% 64.36%
8 7.070638 55.34 77.62% 75.18%
Compared to the feature disabled (threads=0), the overhead is negligible with
the threading code (threads=1), and the gain is already 48% with two threads.
author | Boris Feld <boris.feld@octobus.net> |
---|---|
date | Sun, 17 Dec 2017 04:31:27 +0100 |
parents | ce77b0563228 |
children | 1fb2510cf8c8 |
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#ifndef _HG_BITMANIPULATION_H_ #define _HG_BITMANIPULATION_H_ #include <string.h> #include "compat.h" static inline uint32_t getbe32(const char *c) { const unsigned char *d = (const unsigned char *)c; return ((d[0] << 24) | (d[1] << 16) | (d[2] << 8) | (d[3])); } static inline int16_t getbeint16(const char *c) { const unsigned char *d = (const unsigned char *)c; return ((d[0] << 8) | (d[1])); } static inline uint16_t getbeuint16(const char *c) { const unsigned char *d = (const unsigned char *)c; return ((d[0] << 8) | (d[1])); } static inline void putbe32(uint32_t x, char *c) { c[0] = (x >> 24) & 0xff; c[1] = (x >> 16) & 0xff; c[2] = (x >> 8) & 0xff; c[3] = (x)&0xff; } static inline double getbefloat64(const char *c) { const unsigned char *d = (const unsigned char *)c; double ret; int i; uint64_t t = 0; for (i = 0; i < 8; i++) { t = (t << 8) + d[i]; } memcpy(&ret, &t, sizeof(t)); return ret; } #endif