Re: [PATCH] Add git-grep threads-num param
John Keeping writes: > On Thu, Oct 22, 2015 at 04:23:56PM +0300, Victor Leschuk wrote: >> Hello all, I suggest we make number of git-grep worker threads a >> configuration >> parameter. I have run several tests on systems with different number of CPU >> cores. >> It appeared that the hard-coded number 8 lowers performance on both of my >> systems: >> on my 4-core and 8-core systems the thread number of 4 worked about 20% >> faster than >> default 8. So I think it is better to allow users tune this parameter. > > For git-pack-objects we call the command-line parameter "--threads" and > the config variable "pack.threads". Is there a reason not to use the > same name here (i.e. "--threads" and "grep.threads")? Good suggestion. >> +-t :: >> +--threads-num :: >> +Set number of worker threads to . Default is 8. It is not like you would want to specify different degree of parallelism for every invocation of "grep". The command line option for this feature is expected to be used extremely infrequently, only to defeat a configuration variable that is misconfigured to a wrong value. Squatting on a short-and-sweet single-letter option name is unwarranted for an option like this. >> -for (i = 0; i < ARRAY_SIZE(threads); i++) { >> +threads = xmalloc(sizeof(pthread_t) * opt->num_threads); xcalloc(nmemb, size)? >> @@ -702,6 +704,10 @@ int cmd_grep(int argc, const char **argv, const char >> *prefix) >> N_("show context lines before matches")), >> OPT_INTEGER('A', "after-context", &opt.post_context, >> N_("show context lines after matches")), >> +#ifndef NO_PTHREADS >> +OPT_INTEGER('t', "threads-num", &opt.num_threads, >> +N_("use worker threads")), >> +#endif /* !NO_PTHREADS */ >> OPT_NUMBER_CALLBACK(&opt, N_("shortcut for -C NUM"), >> context_callback), >> OPT_BOOL('p', "show-function", &opt.funcname, >> @@ -910,7 +916,7 @@ int cmd_grep(int argc, const char **argv, const char >> *prefix) >> } >> >> if (use_threads) >> -hit |= wait_all(); >> +hit |= wait_all(&opt); I do not think anybody checked if opt.num_threads is a sensible number after parse_options() returned at this point. There is a code outside the context before this hunk that decides if it makes sense to use threads and turns use_threads to zero, which should be the right place to do the missing sanity check, I thinnk. >> diff --git a/grep.c b/grep.c >> index 7b2b96a..17e6a7c 100644 >> --- a/grep.c >> +++ b/grep.c >> @@ -40,6 +40,9 @@ void init_grep_defaults(void) >> color_set(opt->color_selected, ""); >> color_set(opt->color_sep, GIT_COLOR_CYAN); >> opt->color = -1; >> +#ifndef NO_PTHREADS >> +opt->num_threads = GREP_NUM_THREADS_DEFAULT; >> +#endif /* !NO_PTHREADS */ >> } These #ifndef/#endif's are unnecessary distraction. Just set them unconditionally, even in NO_PTHREADS build (and of course include the field even in NO_PTHREADS build in grep.h). -- To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
RE: [PATCH] Add git-grep threads-num param
Hello John, I haven't noticed the --threads option in pack-objects, I will fix the patch to make naming more uniform. Do you have any comments regarding the functionality? -- Best Regards, Victor From: John Keeping [j...@keeping.me.uk] Sent: Thursday, October 22, 2015 7:23 AM To: Victor Leschuk Cc: git@vger.kernel.org; Victor Leschuk Subject: Re: [PATCH] Add git-grep threads-num param On Thu, Oct 22, 2015 at 04:23:56PM +0300, Victor Leschuk wrote: > Hello all, I suggest we make number of git-grep worker threads a configuration > parameter. I have run several tests on systems with different number of CPU > cores. > It appeared that the hard-coded number 8 lowers performance on both of my > systems: > on my 4-core and 8-core systems the thread number of 4 worked about 20% > faster than > default 8. So I think it is better to allow users tune this parameter. For git-pack-objects we call the command-line parameter "--threads" and the config variable "pack.threads". Is there a reason not to use the same name here (i.e. "--threads" and "grep.threads")? > Signed-off-by: Victor Leschuk > --- > Documentation/config.txt | 4 > Documentation/git-grep.txt | 5 + > builtin/grep.c | 20 +--- > contrib/completion/git-completion.bash | 1 + > grep.c | 15 +++ > grep.h | 4 > 6 files changed, 42 insertions(+), 7 deletions(-) > > diff --git a/Documentation/config.txt b/Documentation/config.txt > index 391a0c3..c3df20c 100644 > --- 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.threadsNum:: > + Number of grep worker threads, use it to tune up performance on > + multicore machines. Default value is 8. > + > 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..e9ca265 100644 > --- a/Documentation/git-grep.txt > +++ b/Documentation/git-grep.txt > @@ -22,6 +22,7 @@ SYNOPSIS > [--color[=] | --no-color] > [--break] [--heading] [-p | --show-function] > [-A ] [-B ] [-C ] > +[-t ] > [-W | --function-context] > [-f ] [-e] > [--and|--or|--not|(|)|-e ...] > @@ -220,6 +221,10 @@ OPTIONS > Show leading lines, and place a line containing > `--` between contiguous groups of matches. > > +-t :: > +--threads-num :: > + Set number of worker threads to . Default is 8. > + > -W:: > --function-context:: > Show the surrounding text from the previous line containing a > diff --git a/builtin/grep.c b/builtin/grep.c > index d04f440..9b4fc47 100644 > --- a/builtin/grep.c > +++ b/builtin/grep.c > @@ -27,8 +27,7 @@ static char const * const grep_usage[] = { > static int use_threads = 1; > > #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 > @@ -206,7 +205,8 @@ static void start_threads(struct grep_opt *opt) > strbuf_init(&todo[i].out, 0); > } > > - for (i = 0; i < ARRAY_SIZE(threads); i++) { > + threads = xmalloc(sizeof(pthread_t) * opt->num_threads); > + for (i = 0; i < opt->num_threads; i++) { > int err; > struct grep_opt *o = grep_opt_dup(opt); > o->output = strbuf_out; > @@ -220,7 +220,7 @@ static void start_threads(struct grep_opt *opt) > } > } > > -static int wait_all(void) > +static int wait_all(struct grep_opt *opt) > { > int hit = 0; > int i; > @@ -238,12 +238,14 @@ static int wait_all(void) > pthread_cond_broadcast(&cond_add); > grep_unlock(); > > - for (i = 0; i < ARRAY_SIZE(threads); i++) { > + for (i = 0; i < opt->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); > @@ -256,7
Re: [PATCH] Add git-grep threads-num param
On Thu, Oct 22, 2015 at 04:23:56PM +0300, Victor Leschuk wrote: > Hello all, I suggest we make number of git-grep worker threads a configuration > parameter. I have run several tests on systems with different number of CPU > cores. > It appeared that the hard-coded number 8 lowers performance on both of my > systems: > on my 4-core and 8-core systems the thread number of 4 worked about 20% > faster than > default 8. So I think it is better to allow users tune this parameter. For git-pack-objects we call the command-line parameter "--threads" and the config variable "pack.threads". Is there a reason not to use the same name here (i.e. "--threads" and "grep.threads")? > Signed-off-by: Victor Leschuk > --- > Documentation/config.txt | 4 > Documentation/git-grep.txt | 5 + > builtin/grep.c | 20 +--- > contrib/completion/git-completion.bash | 1 + > grep.c | 15 +++ > grep.h | 4 > 6 files changed, 42 insertions(+), 7 deletions(-) > > diff --git a/Documentation/config.txt b/Documentation/config.txt > index 391a0c3..c3df20c 100644 > --- 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.threadsNum:: > + Number of grep worker threads, use it to tune up performance on > + multicore machines. Default value is 8. > + > 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..e9ca265 100644 > --- a/Documentation/git-grep.txt > +++ b/Documentation/git-grep.txt > @@ -22,6 +22,7 @@ SYNOPSIS > [--color[=] | --no-color] > [--break] [--heading] [-p | --show-function] > [-A ] [-B ] [-C ] > +[-t ] > [-W | --function-context] > [-f ] [-e] > [--and|--or|--not|(|)|-e ...] > @@ -220,6 +221,10 @@ OPTIONS > Show leading lines, and place a line containing > `--` between contiguous groups of matches. > > +-t :: > +--threads-num :: > + Set number of worker threads to . Default is 8. > + > -W:: > --function-context:: > Show the surrounding text from the previous line containing a > diff --git a/builtin/grep.c b/builtin/grep.c > index d04f440..9b4fc47 100644 > --- a/builtin/grep.c > +++ b/builtin/grep.c > @@ -27,8 +27,7 @@ static char const * const grep_usage[] = { > static int use_threads = 1; > > #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 > @@ -206,7 +205,8 @@ static void start_threads(struct grep_opt *opt) > strbuf_init(&todo[i].out, 0); > } > > - for (i = 0; i < ARRAY_SIZE(threads); i++) { > + threads = xmalloc(sizeof(pthread_t) * opt->num_threads); > + for (i = 0; i < opt->num_threads; i++) { > int err; > struct grep_opt *o = grep_opt_dup(opt); > o->output = strbuf_out; > @@ -220,7 +220,7 @@ static void start_threads(struct grep_opt *opt) > } > } > > -static int wait_all(void) > +static int wait_all(struct grep_opt *opt) > { > int hit = 0; > int i; > @@ -238,12 +238,14 @@ static int wait_all(void) > pthread_cond_broadcast(&cond_add); > grep_unlock(); > > - for (i = 0; i < ARRAY_SIZE(threads); i++) { > + for (i = 0; i < opt->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); > @@ -256,7 +258,7 @@ static int wait_all(void) > } > #else /* !NO_PTHREADS */ > > -static int wait_all(void) > +static int wait_all(struct grep_opt *opt) > { > return 0; > } > @@ -702,6 +704,10 @@ int cmd_grep(int argc, const char **argv, const char > *prefix) > N_("show context lines before matches")), > OPT_INTEGER('A', "after-context", &opt.post_context, > N_("show context lines after matches")), > +#ifndef NO_PTHREADS > + OPT_INTEGER('t', "threads-num", &opt.num_threads, > + N_("use worker threads")), > +#endif /* !NO_PTHREADS */ > OPT_NUMBER_CALLBACK(&opt, N_("shortcut for -C NUM"), > context_callback), > OPT_BOOL('p', "show-function", &opt.funcname, > @@ -910,7 +916,7 @@ int cmd_grep(int argc, const char **