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From: Ben Peart <peartben@gmail.com>
To: Duy Nguyen <pclouds@gmail.com>
Cc: Git Mailing List <git@vger.kernel.org>,
	Junio C Hamano <gitster@pobox.com>, Jeff King <peff@peff.net>
Subject: Re: [PATCH v2 06/10] preload-index.c: remove #ifdef NO_PTHREADS
Date: Mon, 29 Oct 2018 14:05:58 -0400	[thread overview]
Message-ID: <2935e3e8-c529-4292-baa3-fc3c9074028b@gmail.com> (raw)
In-Reply-To: <CACsJy8CYnngeA8JcFy83qYxKj3saB21Y32VV3R5o1PY_tkAq5Q@mail.gmail.com>



On 10/29/2018 1:26 PM, Duy Nguyen wrote:
> On Mon, Oct 29, 2018 at 6:21 PM Ben Peart <peartben@gmail.com> wrote:
>> @@ -114,6 +104,9 @@ static void preload_index(struct index_state *index,
>>           threads = index->cache_nr / THREAD_COST;
>>           if ((index->cache_nr > 1) && (threads < 2) &&
>> git_env_bool("GIT_TEST_PRELOAD_INDEX", 0))
>>                   threads = 2;
>> +       cpus = online_cpus();
>> +       if (threads > cpus)
>> +               threads = cpus;
>>           if (threads < 2)
>>                   return;
>>           trace_performance_enter();
> 
> Capping the number of threads to online_cpus() does not always make
> sense. In this case (or at least the original use case where we stat()
> over nfs) we want to issue as many requests to nfs server as possible
> to reduce latency and it has nothing to do with how many cores we
> have. Using more threads than cores might make sense since threads are
> blocked by nfs client, but we still want to send more to the server.
> 

That makes sense.  Some test will be necessary then.

I guess HAVE_THREADS is functionally the same as online_cpus() == 1. 
For some reason, I prefer the latter - probably because I'm typically 
already calling it and so it doesn't feel like a 'special' value/test I 
have to remember. I just know I need to make sure the logic works 
correctly with any number of cps greater than zero. :-)

  reply	other threads:[~2018-10-29 18:06 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 [this message]
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
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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