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
