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Re: [PATCH 07/10] preload-index.c: remove #ifdef NO_PTHREADS






On 10/27/2018 3:10 AM, Nguyễn Thái Ngọc Duy wrote:
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@xxxxxxxxx>
---
  preload-index.c | 15 ++-------------
  1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/preload-index.c b/preload-index.c
index 9e7152ab14..0e24886aca 100644
--- a/preload-index.c
+++ b/preload-index.c
@@ -7,17 +7,7 @@
  #include "fsmonitor.h"
  #include "config.h"
  #include "progress.h"
-
-#ifdef NO_PTHREADS
-static void preload_index(struct index_state *index,
-			  const struct pathspec *pathspec,
-			  unsigned int refresh_flags)
-{
-	; /* nothing */
-}
-#else
-
-#include <pthread.h>
+#include "thread-utils.h"
/*
   * Mostly randomly chosen maximum thread counts: we
@@ -108,7 +98,7 @@ static void preload_index(struct index_state *index,
  	struct thread_data data[MAX_PARALLEL];
  	struct progress_data pd;
- if (!core_preload_index)
+	if (!HAVE_THREADS || !core_preload_index)

I also "hoped in general that the non-threaded code paths could mostly just collapse into the same as the "threads == 1" cases, and we wouldn't have to "are threads even supported" in a lot of places."

In this case, if we cap the threads to online_cpus() the later test for 'if (threads < 2)' would do that. I haven't measured this specific case but in the other cases I have measured, having more threads than cpus did not result in a performance win.

  		return;
threads = index->cache_nr / THREAD_COST;
@@ -151,7 +141,6 @@ static void preload_index(struct index_state *index,
trace_performance_leave("preload index");
  }
-#endif
int read_index_preload(struct index_state *index,
  		       const struct pathspec *pathspec,