view mercurial/bdiff.h @ 35767:5f5fb279fd39

streamclone: also stream caches to the client

When stream clone is used over bundle2, relevant cache files are also streamed.
This is expected to be a massive performance win for clone since no important
cache will have to be recomputed.

Some performance numbers:

(All times are wall-clock times in seconds, 2 attempts per case.)

# Mozilla-Central

## Clone over ssh over lan
V1 streaming: 234.3 239.6
V2 streaming: 248.4 243.7

## Clone over ssh over Internet
V1 streaming: 175.5 110.9
V2 streaming: 109.1 111.0

## Clone over HTTP over lan
V1 streaming: 105.3 105.6
V2 streaming: 112.7 111.4

## Clone over HTTP over internet
V1 streaming: 105.6 114.6
V2 streaming: 226.7 225.9

## Hg tags
V1 streaming (no cache): 1.084 1.071
V2 streaming (cache):    0.312 0.325

## Hg branches
V1 streaming (no cache):   14.047 14.148
V2 streaming (with cache):  0.312  0.333

# Pypy

## Clone over ssh over internet
V1 streaming: 29.4 30.1
V2 streaming: 31.2 30.1

## Clone over http over internet
V1 streaming: 29.7 29.7
V2 streaming: 75.2 72.9

(since ssh and lan are not affected, there seems to be an issue with how we
read/write the http stream on connection with latency, unrelated to the format)

## Hg tags
V1 streaming (no cache):   1.752 1.664
V2 streaming (with cache): 0.274 0.260

## Hg branches
V1 streaming (no cache):   4.469 4.728
V2 streaming (with cache): 0.318 0.321

# Private repository:
    * 500K revision revisions
    * 11K topological heads
    * 28K branch heads

## hg tags
no cache:   1543.332
with cache:    4.900

## hg branches
no cache:   91.828
with cache:  2.955

#ifndef _HG_BDIFF_H_
#define _HG_BDIFF_H_

#include "compat.h"

struct bdiff_line {
	int hash, n, e;
	ssize_t len;
	const char *l;
};

struct bdiff_hunk;
struct bdiff_hunk {
	int a1, a2, b1, b2;
	struct bdiff_hunk *next;
};

int bdiff_splitlines(const char *a, ssize_t len, struct bdiff_line **lr);
int bdiff_diff(struct bdiff_line *a, int an, struct bdiff_line *b, int bn,
               struct bdiff_hunk *base);
void bdiff_freehunks(struct bdiff_hunk *l);

#endif