Andrew's git - gitweb.git/blob

0a4e2933bb6eca181b529c288aa9ac017138c349
   1/*
   2 * Copyright (C) 2008 Linus Torvalds
   3 */
   4#include "cache.h"
   5#include "pathspec.h"
   6#include "dir.h"
   7#include "fsmonitor.h"
   8#include "config.h"
   9
  10#ifdef NO_PTHREADS
  11static void preload_index(struct index_state *index,
  12                          const struct pathspec *pathspec)
  13{
  14        ; /* nothing */
  15}
  16#else
  17
  18#include <pthread.h>
  19
  20/*
  21 * Mostly randomly chosen maximum thread counts: we
  22 * cap the parallelism to 20 threads, and we want
  23 * to have at least 500 lstat's per thread for it to
  24 * be worth starting a thread.
  25 */
  26#define MAX_PARALLEL (20)
  27#define THREAD_COST (500)
  28
  29struct thread_data {
  30        pthread_t pthread;
  31        struct index_state *index;
  32        struct pathspec pathspec;
  33        int offset, nr;
  34};
  35
  36static void *preload_thread(void *_data)
  37{
  38        int nr;
  39        struct thread_data *p = _data;
  40        struct index_state *index = p->index;
  41        struct cache_entry **cep = index->cache + p->offset;
  42        struct cache_def cache = CACHE_DEF_INIT;
  43
  44        nr = p->nr;
  45        if (nr + p->offset > index->cache_nr)
  46                nr = index->cache_nr - p->offset;
  47
  48        do {
  49                struct cache_entry *ce = *cep++;
  50                struct stat st;
  51
  52                if (ce_stage(ce))
  53                        continue;
  54                if (S_ISGITLINK(ce->ce_mode))
  55                        continue;
  56                if (ce_uptodate(ce))
  57                        continue;
  58                if (ce_skip_worktree(ce))
  59                        continue;
  60                if (ce->ce_flags & CE_FSMONITOR_VALID)
  61                        continue;
  62                if (!ce_path_match(index, ce, &p->pathspec, NULL))
  63                        continue;
  64                if (threaded_has_symlink_leading_path(&cache, ce->name, ce_namelen(ce)))
  65                        continue;
  66                if (lstat(ce->name, &st))
  67                        continue;
  68                if (ie_match_stat(index, ce, &st, CE_MATCH_RACY_IS_DIRTY|CE_MATCH_IGNORE_FSMONITOR))
  69                        continue;
  70                ce_mark_uptodate(ce);
  71                mark_fsmonitor_valid(ce);
  72        } while (--nr > 0);
  73        cache_def_clear(&cache);
  74        return NULL;
  75}
  76
  77static void preload_index(struct index_state *index,
  78                          const struct pathspec *pathspec)
  79{
  80        int threads, i, work, offset;
  81        struct thread_data data[MAX_PARALLEL];
  82        uint64_t start = getnanotime();
  83
  84        if (!core_preload_index)
  85                return;
  86
  87        threads = index->cache_nr / THREAD_COST;
  88        if ((index->cache_nr > 1) && (threads < 2) && git_env_bool("GIT_FORCE_PRELOAD_TEST", 0))
  89                threads = 2;
  90        if (threads < 2)
  91                return;
  92        if (threads > MAX_PARALLEL)
  93                threads = MAX_PARALLEL;
  94        offset = 0;
  95        work = DIV_ROUND_UP(index->cache_nr, threads);
  96        memset(&data, 0, sizeof(data));
  97        for (i = 0; i < threads; i++) {
  98                struct thread_data *p = data+i;
  99                p->index = index;
 100                if (pathspec)
 101                        copy_pathspec(&p->pathspec, pathspec);
 102                p->offset = offset;
 103                p->nr = work;
 104                offset += work;
 105                if (pthread_create(&p->pthread, NULL, preload_thread, p))
 106                        die("unable to create threaded lstat");
 107        }
 108        for (i = 0; i < threads; i++) {
 109                struct thread_data *p = data+i;
 110                if (pthread_join(p->pthread, NULL))
 111                        die("unable to join threaded lstat");
 112        }
 113        trace_performance_since(start, "preload index");
 114}
 115#endif
 116
 117int read_index_preload(struct index_state *index,
 118                       const struct pathspec *pathspec)
 119{
 120        int retval = read_index(index);
 121
 122        preload_index(index, pathspec);
 123        return retval;
 124}