Mercurial > hg-stable
view mercurial/bitmanipulation.h @ 39576:84bf6ded9317
wireprotoframing: buffer emitted data to reduce frame count
An upcoming commit introduces a wire protocol command that can emit
hundreds of thousands of small objects. Without a buffering layer,
we would emit a single, small frame for every object. Performance
profiling revealed this to be a source of significant overhead for
both client and server.
This commit introduces a very crude buffering layer so that we emit
fewer, bigger frames in such a scenario. This code will likely get
rewritten in the future to be part of the streams API, as we'll
need a similar strategy for compressing data. I don't want to think
about it too much at the moment though.
server
before: user 32.500+0.000 sys 1.160+0.000
after: user 20.230+0.010 sys 0.180+0.000
client
before: user 133.400+0.000 sys 93.120+0.000
after: user 68.370+0.000 sys 32.950+0.000
This appears to indicate we have significant overhead in the frame
processing code on both client and server. It might be worth profiling
that at some point...
Differential Revision: https://phab.mercurial-scm.org/D4473
author | Gregory Szorc <gregory.szorc@gmail.com> |
---|---|
date | Wed, 29 Aug 2018 16:43:17 -0700 |
parents | 1fb2510cf8c8 |
children | eed42f1c22d6 |
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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 ((((uint32_t)d[0]) << 24) | (((uint32_t)d[1]) << 16) | (((uint32_t)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