From: Ben Peart <peartben@gmail.com>
To: "Jeff King" <peff@peff.net>, "Nguyễn Thái Ngọc Duy" <pclouds@gmail.com>
Cc: git@vger.kernel.org, gitster@pobox.com
Subject: Re: [PATCH v2 08/10] read-cache.c: remove #ifdef NO_PTHREADS
Date: Mon, 29 Oct 2018 13:23:36 -0400 [thread overview]
Message-ID: <61d354e9-dd40-14a8-29dc-d989dd5631af@gmail.com> (raw)
In-Reply-To: <20181029143033.GF17668@sigill.intra.peff.net>
On 10/29/2018 10:30 AM, Jeff King wrote:
> On Sat, Oct 27, 2018 at 07:30:06PM +0200, Nguyễn Thái Ngọc Duy wrote:
>
>> -#ifndef NO_PTHREADS
>> - nr_threads = git_config_get_index_threads();
>> + if (HAVE_THREADS) {
>> + nr_threads = git_config_get_index_threads();
>>
>> - /* TODO: does creating more threads than cores help? */
>> - if (!nr_threads) {
>> - nr_threads = istate->cache_nr / THREAD_COST;
>> - cpus = online_cpus();
>> - if (nr_threads > cpus)
>> - nr_threads = cpus;
>> + /* TODO: does creating more threads than cores help? */
>> + if (!nr_threads) {
>> + nr_threads = istate->cache_nr / THREAD_COST;
>> + cpus = online_cpus();
>> + if (nr_threads > cpus)
>> + nr_threads = cpus;
>> + }
>> + } else {
>> + nr_threads = 1;
>> }
>
> I'd have thought we could just rely on online_cpus() returning 1 here to
> avoid having to ask "do we even have thread support?". But I guess that
> TODO comment implies that we might one day two 2 threads on a single
> CPU.
>
> -Peff
>
And here is the patch I created when testing out the idea of removing
NO_PTHREADS. It doesn't require any 'HAVE_THREADS' tests.
diff --git a/read-cache.c b/read-cache.c
index 1df5c16dbc..1f088799fc 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1920,19 +1920,15 @@ struct index_entry_offset_table
struct index_entry_offset entries[FLEX_ARRAY];
};
-#ifndef NO_PTHREADS
static struct index_entry_offset_table *read_ieot_extension(const char
*mmap, size_t mmap_size, size_t offset
);
static void write_ieot_extension(struct strbuf *sb, struct
index_entry_offset_table *ieot);
-#endif
static size_t read_eoie_extension(const char *mmap, size_t mmap_size);
static void write_eoie_extension(struct strbuf *sb, git_hash_ctx
*eoie_context, size_t offset);
struct load_index_extensions
{
-#ifndef NO_PTHREADS
pthread_t pthread;
-#endif
struct index_state *istate;
const char *mmap;
size_t mmap_size;
@@ -2010,8 +2006,6 @@ static unsigned long load_all_cache_entries(struct
index_state *istate,
return consumed;
}
-#ifndef NO_PTHREADS
-
/*
* Mostly randomly chosen maximum thread counts: we
* cap the parallelism to online_cpus() threads, and we want
@@ -2122,7 +2116,6 @@ static unsigned long
load_cache_entries_threaded(struct index_state *istate, con
return consumed;
}
-#endif
/* remember to discard_cache() before reading a different cache! */
int do_read_index(struct index_state *istate, const char *path, int
must_exist)
@@ -2135,10 +2128,8 @@ int do_read_index(struct index_state *istate,
const char *path, int must_exist)
size_t mmap_size;
struct load_index_extensions p;
size_t extension_offset = 0;
-#ifndef NO_PTHREADS
int nr_threads, cpus;
struct index_entry_offset_table *ieot = NULL;
-#endif
if (istate->initialized)
return istate->cache_nr;
@@ -2181,16 +2172,12 @@ int do_read_index(struct index_state *istate,
const char *path, int must_exist
)
src_offset = sizeof(*hdr);
-#ifndef NO_PTHREADS
nr_threads = git_config_get_index_threads();
-
- /* TODO: does creating more threads than cores help? */
- if (!nr_threads) {
+ if (!nr_threads)
nr_threads = istate->cache_nr / THREAD_COST;
- cpus = online_cpus();
- if (nr_threads > cpus)
- nr_threads = cpus;
- }
+ cpus = online_cpus();
+ if (nr_threads > cpus)
+ nr_threads = cpus;
if (nr_threads > 1) {
extension_offset = read_eoie_extension(mmap, mmap_size);
@@ -2219,22 +2206,16 @@ int do_read_index(struct index_state *istate,
const char *path, int must_exist
)
} else {
src_offset += load_all_cache_entries(istate, mmap,
mmap_size, src_offset);
}
-#else
- src_offset += load_all_cache_entries(istate, mmap, mmap_size,
src_offset);
-#endif
istate->timestamp.sec = st.st_mtime;
istate->timestamp.nsec = ST_MTIME_NSEC(st);
/* if we created a thread, join it otherwise load the
extensions on the primary thread */
-#ifndef NO_PTHREADS
if (extension_offset) {
int ret = pthread_join(p.pthread, NULL);
if (ret)
die(_("unable to join load_index_extensions
thread: %s"), strerror(ret));
- }
-#endif
- if (!extension_offset) {
+ } else {
p.src_offset = src_offset;
load_index_extensions(&p);
}
@@ -2756,7 +2737,6 @@ static int do_write_index(struct index_state
*istate, struct tempfile *tempfile,
if (ce_write(&c, newfd, &hdr, sizeof(hdr)) < 0)
return -1;
-#ifndef NO_PTHREADS
nr_threads = git_config_get_index_threads();
if (nr_threads != 1) {
int ieot_blocks, cpus;
@@ -2787,7 +2767,6 @@ static int do_write_index(struct index_state
*istate, struct tempfile *tempfile,
ieot_entries = DIV_ROUND_UP(entries, ieot_blocks);
}
}
-#endif
offset = lseek(newfd, 0, SEEK_CUR);
if (offset < 0) {
@@ -2871,7 +2850,6 @@ static int do_write_index(struct index_state
*istate, struct tempfile *tempfile,
* strip_extensions parameter as we need it when loading the shared
* index.
*/
-#ifndef NO_PTHREADS
if (ieot) {
struct strbuf sb = STRBUF_INIT;
@@ -2883,7 +2861,6 @@ static int do_write_index(struct index_state
*istate, struct tempfile *tempfile,
if (err)
return -1;
}
-#endif
if (!strip_extensions && istate->split_index) {
struct strbuf sb = STRBUF_INIT;
@@ -3469,7 +3446,6 @@ static void write_eoie_extension(struct strbuf
*sb, git_hash_ctx *eoie_context,
strbuf_add(sb, hash, the_hash_algo->rawsz);
}
-#ifndef NO_PTHREADS
#define IEOT_VERSION (1)
static struct index_entry_offset_table *read_ieot_extension(const char
*mmap, size_t mmap_size, size_t offset
)
@@ -3542,4 +3518,3 @@ static void write_ieot_extension(struct strbuf
*sb, struct index_entry_offset_ta
strbuf_add(sb, &buffer, sizeof(uint32_t));
}
}
-#endif
next prev parent reply other threads:[~2018-10-29 17:23 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-10-27 7:09 [PATCH 00/10] Reduce #ifdef NO_PTHREADS Nguyễn Thái Ngọc Duy
2018-10-27 7:09 ` [PATCH 01/10] thread-utils: macros to unconditionally compile pthreads API Nguyễn Thái Ngọc Duy
2018-10-27 7:31 ` Jeff King
2018-10-27 7:40 ` Duy Nguyen
2018-10-27 8:15 ` Jeff King
2018-10-27 14:43 ` Duy Nguyen
2018-10-27 7:09 ` [PATCH 02/10] index-pack: remove #ifdef NO_PTHREADS Nguyễn Thái Ngọc Duy
2018-10-27 7:34 ` Jeff King
2018-10-27 7:09 ` [PATCH 03/10] name-hash.c: " Nguyễn Thái Ngọc Duy
2018-10-27 7:09 ` [PATCH 04/10] attr.c: " Nguyễn Thái Ngọc Duy
2018-10-27 7:09 ` [PATCH 05/10] send-pack.c: " Nguyễn Thái Ngọc Duy
2018-10-27 7:39 ` Jeff King
2018-10-27 7:09 ` [PATCH 06/10] grep: " Nguyễn Thái Ngọc Duy
2018-10-27 7:44 ` Jeff King
2018-10-29 2:16 ` Junio C Hamano
2018-10-29 14:25 ` Jeff King
2018-10-29 16:01 ` Duy Nguyen
2018-10-29 16:20 ` Jeff King
2018-10-30 1:27 ` Junio C Hamano
2018-10-27 7:10 ` [PATCH 07/10] preload-index.c: " Nguyễn Thái Ngọc Duy
2018-10-29 16:52 ` Ben Peart
2018-10-27 7:10 ` [PATCH 08/10] pack-objects: " Nguyễn Thái Ngọc Duy
2018-10-27 7:10 ` [PATCH 09/10] read-cache.c: " Nguyễn Thái Ngọc Duy
2018-10-29 17:05 ` Ben Peart
2018-10-29 17:21 ` Duy Nguyen
2018-10-29 17:58 ` Ben Peart
2018-10-30 1:44 ` Junio C Hamano
2018-10-27 7:10 ` [PATCH 10/10] Clean up pthread_create() error handling Nguyễn Thái Ngọc Duy
2018-10-27 7:24 ` [PATCH 00/10] Reduce #ifdef NO_PTHREADS Jeff King
2018-10-27 8:13 ` Jeff King
2018-10-27 17:07 ` Duy Nguyen
2018-10-27 17:29 ` [PATCH v2 " Nguyễn Thái Ngọc Duy
2018-10-27 17:29 ` [PATCH v2 01/10] thread-utils: macros to unconditionally compile pthreads API Nguyễn Thái Ngọc Duy
2018-10-27 17:30 ` [PATCH v2 02/10] index-pack: remove #ifdef NO_PTHREADS Nguyễn Thái Ngọc Duy
2018-10-27 17:30 ` [PATCH v2 03/10] name-hash.c: " Nguyễn Thái Ngọc Duy
2018-10-27 17:30 ` [PATCH v2 04/10] attr.c: " Nguyễn Thái Ngọc Duy
2018-10-27 17:30 ` [PATCH v2 05/10] grep: " Nguyễn Thái Ngọc Duy
2018-10-27 17:30 ` [PATCH v2 06/10] preload-index.c: " Nguyễn Thái Ngọc Duy
2018-10-29 17:21 ` Ben Peart
2018-10-29 17:26 ` Duy Nguyen
2018-10-29 18:05 ` Ben Peart
2018-10-29 20:11 ` Jeff King
2018-10-27 17:30 ` [PATCH v2 07/10] pack-objects: " Nguyễn Thái Ngọc Duy
2018-10-27 17:30 ` [PATCH v2 08/10] read-cache.c: " Nguyễn Thái Ngọc Duy
2018-10-29 14:30 ` Jeff King
2018-10-29 17:07 ` Ben Peart
2018-10-29 17:23 ` Ben Peart [this message]
2018-10-27 17:30 ` [PATCH v2 09/10] Clean up pthread_create() error handling Nguyễn Thái Ngọc Duy
2018-10-27 17:30 ` [PATCH v2 10/10] read-cache.c: initialize copy_len to shut up gcc 8 Nguyễn Thái Ngọc Duy
2018-10-29 14:31 ` Jeff King
2018-11-03 8:48 ` [PATCH v3 00/14] Reduce #ifdef NO_PTHREADS Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 01/14] thread-utils: macros to unconditionally compile pthreads API Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 02/14] run-command.h: include thread-utils.h instead of pthread.h Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 03/14] send-pack.c: move async's #ifdef NO_PTHREADS back to run-command.c Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 04/14] index-pack: remove #ifdef NO_PTHREADS Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 05/14] name-hash.c: " Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 06/14] attr.c: " Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 07/14] grep: " Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 08/14] grep: clean up num_threads handling Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 09/14] preload-index.c: remove #ifdef NO_PTHREADS Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 10/14] pack-objects: " Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 11/14] read-cache.c: " Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 12/14] read-cache.c: reduce branching based on HAVE_THREADS Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 13/14] read-cache.c: initialize copy_len to shut up gcc 8 Nguyễn Thái Ngọc Duy
2018-11-03 8:48 ` [PATCH v3 14/14] Clean up pthread_create() error handling Nguyễn Thái Ngọc Duy
2018-11-06 4:51 ` [PATCH v3 00/14] Reduce #ifdef NO_PTHREADS Junio C Hamano
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