grep: add --threads=<num> option and grep.threads configuration

"git grep" can now be configured (or told from the command line) how
many threads to use when searching in the working tree files.

Signed-off-by: Victor Leschuk <vleschuk@accesssoftek.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 391a0c3..ff21799 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -1447,6 +1447,10 @@ grep.extendedRegexp::
        option is ignored when the 'grep.patternType' option is set to a value
        other than 'default'.
 
+grep.threads::
+       Number of grep worker threads to use.
+       See `grep.threads` in linkgit:git-grep[1] for more information.
+
 gpg.program::
        Use this custom program instead of "gpg" found on $PATH when
        making or verifying a PGP signature. The program must support the

diff --git a/Documentation/git-grep.txt b/Documentation/git-grep.txt
index 4a44d6d..35aada1 100644 (file)
--- a/Documentation/git-grep.txt
+++ b/Documentation/git-grep.txt
@@ -23,6 +23,7 @@ SYNOPSIS
           [--break] [--heading] [-p | --show-function]
           [-A <post-context>] [-B <pre-context>] [-C <context>]
           [-W | --function-context]
+          [--threads <num>]
           [-f <file>] [-e] <pattern>
           [--and|--or|--not|(|)|-e <pattern>...]
           [ [--[no-]exclude-standard] [--cached | --no-index | --untracked] | <tree>...]
@@ -53,6 +54,10 @@ grep.extendedRegexp::
        option is ignored when the 'grep.patternType' option is set to a value
        other than 'default'.
 
+grep.threads::
+       Number of grep worker threads to use.  If unset (or set to 0),
+       8 threads are used by default (for now).
+
 grep.fullName::
        If set to true, enable '--full-name' option by default.
 
@@ -227,6 +232,10 @@ OPTIONS
        effectively showing the whole function in which the match was
        found.
 
+--threads <num>::
+       Number of grep worker threads to use.
+       See `grep.threads` in 'CONFIGURATION' for more information.
+
 -f <file>::
        Read patterns from <file>, one per line.
 

diff --git a/builtin/grep.c b/builtin/grep.c
index a892967..97d9ec3 100644 (file)
--- a/builtin/grep.c
+++ b/builtin/grep.c
@@ -24,11 +24,11 @@ static char const * const grep_usage[] = {
        NULL
 };
 
-static int use_threads = 1;
+#define GREP_NUM_THREADS_DEFAULT 8
+static int num_threads;
 
 #ifndef NO_PTHREADS
-#define THREADS 8
-static pthread_t threads[THREADS];
+static pthread_t *threads;
 
 /* We use one producer thread and THREADS consumer
  * threads. The producer adds struct work_items to 'todo' and the
@@ -63,13 +63,13 @@ static pthread_mutex_t grep_mutex;
 
 static inline void grep_lock(void)
 {
-       if (use_threads)
+       if (num_threads)
                pthread_mutex_lock(&grep_mutex);
 }
 
 static inline void grep_unlock(void)
 {
-       if (use_threads)
+       if (num_threads)
                pthread_mutex_unlock(&grep_mutex);
 }
 
@@ -206,7 +206,8 @@ static void start_threads(struct grep_opt *opt)
                strbuf_init(&todo[i].out, 0);
        }
 
-       for (i = 0; i < ARRAY_SIZE(threads); i++) {
+       threads = xcalloc(num_threads, sizeof(*threads));
+       for (i = 0; i < num_threads; i++) {
                int err;
                struct grep_opt *o = grep_opt_dup(opt);
                o->output = strbuf_out;
@@ -238,12 +239,14 @@ static int wait_all(void)
        pthread_cond_broadcast(&cond_add);
        grep_unlock();
 
-       for (i = 0; i < ARRAY_SIZE(threads); i++) {
+       for (i = 0; i < num_threads; i++) {
                void *h;
                pthread_join(threads[i], &h);
                hit |= (int) (intptr_t) h;
        }
 
+       free(threads);
+
        pthread_mutex_destroy(&grep_mutex);
        pthread_mutex_destroy(&grep_read_mutex);
        pthread_mutex_destroy(&grep_attr_mutex);
@@ -267,6 +270,14 @@ static int grep_cmd_config(const char *var, const char *value, void *cb)
        int st = grep_config(var, value, cb);
        if (git_color_default_config(var, value, cb) < 0)
                st = -1;
+
+       if (!strcmp(var, "grep.threads")) {
+               num_threads = git_config_int(var, value);
+               if (num_threads < 0)
+                       die(_("invalid number of threads specified (%d) for %s"),
+                           num_threads, var);
+       }
+
        return st;
 }
 
@@ -294,7 +305,7 @@ static int grep_sha1(struct grep_opt *opt, const unsigned char *sha1,
        }
 
 #ifndef NO_PTHREADS
-       if (use_threads) {
+       if (num_threads) {
                add_work(opt, GREP_SOURCE_SHA1, pathbuf.buf, path, sha1);
                strbuf_release(&pathbuf);
                return 0;
@@ -323,7 +334,7 @@ static int grep_file(struct grep_opt *opt, const char *filename)
                strbuf_addstr(&buf, filename);
 
 #ifndef NO_PTHREADS
-       if (use_threads) {
+       if (num_threads) {
                add_work(opt, GREP_SOURCE_FILE, buf.buf, filename, filename);
                strbuf_release(&buf);
                return 0;
@@ -702,6 +713,8 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
                        N_("show <n> context lines before matches")),
                OPT_INTEGER('A', "after-context", &opt.post_context,
                        N_("show <n> context lines after matches")),
+               OPT_INTEGER(0, "threads", &num_threads,
+                       N_("use <n> worker threads")),
                OPT_NUMBER_CALLBACK(&opt, N_("shortcut for -C NUM"),
                        context_callback),
                OPT_BOOL('p', "show-function", &opt.funcname,
@@ -832,13 +845,17 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
 
 #ifndef NO_PTHREADS
        if (list.nr || cached || show_in_pager)
-               use_threads = 0;
+               num_threads = 0;
+       else if (num_threads == 0)
+               num_threads = GREP_NUM_THREADS_DEFAULT;
+       else if (num_threads < 0)
+               die(_("invalid number of threads specified (%d)"), num_threads);
 #else
-       use_threads = 0;
+       num_threads = 0;
 #endif
 
 #ifndef NO_PTHREADS
-       if (use_threads) {
+       if (num_threads) {
                if (!(opt.name_only || opt.unmatch_name_only || opt.count)
                    && (opt.pre_context || opt.post_context ||
                        opt.file_break || opt.funcbody))
@@ -908,7 +925,7 @@ int cmd_grep(int argc, const char **argv, const char *prefix)
                hit = grep_objects(&opt, &pathspec, &list);
        }
 
-       if (use_threads)
+       if (num_threads)
                hit |= wait_all();
        if (hit && show_in_pager)
                run_pager(&opt, prefix);

diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash
index 482ca84..390d9c0 100644 (file)
--- a/contrib/completion/git-completion.bash
+++ b/contrib/completion/git-completion.bash
@@ -1310,6 +1310,7 @@ _git_grep ()
                        --full-name --line-number
                        --extended-regexp --basic-regexp --fixed-strings
                        --perl-regexp
+                       --threads
                        --files-with-matches --name-only
                        --files-without-match
                        --max-depth