threaded delta search: add pack.threads config variable

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 866e0534b8843af3c1789becd06b244162632d01..015910f27a450cdaec80f3bfc2679243126736c0 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -630,9 +630,17 @@ pack.deltaCacheSize::
        A value of 0 means no limit. Defaults to 0.
 
 pack.deltaCacheLimit::
-       The maxium size of a delta, that is cached in
+       The maximum size of a delta, that is cached in
        gitlink:git-pack-objects[1]. Defaults to 1000.
 
+pack.threads::
+       Specifies the number of threads to spawn when searching for best
+       delta matches.  This requires that gitlink:git-pack-objects[1]
+       be compiled with pthreads otherwise this option is ignored with a
+       warning. This is meant to reduce packing time on multiprocessor
+       machines. The required amount of memory for the delta search window
+       is however multiplied by the number of threads.
+
 pull.octopus::
        The default merge strategy to use when pulling multiple branches
        at once.

diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index af12e454e183d69eb34c369e2c789a7c0a921b80..e091bcbda9233f8b1bfe25f6aa4d702614d42435 100644 (file)
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -1746,6 +1746,17 @@ static int git_pack_config(const char *k, const char *v)
                cache_max_small_delta_size = git_config_int(k, v);
                return 0;
        }
+       if (!strcmp(k, "pack.threads")) {
+               delta_search_threads = git_config_int(k, v);
+               if (delta_search_threads < 1)
+                       die("invalid number of threads specified (%d)",
+                           delta_search_threads);
+#ifndef THREADED_DELTA_SEARCH
+               if (delta_search_threads > 1)
+                       warning("no threads support, ignoring %s", k);
+#endif
+               return 0;
+       }
        return git_default_config(k, v);
 }