From patchwork Tue Nov  1 11:33:01 2011
Content-Type: text/plain; charset="utf-8"
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
X-Patchwork-Submitter: niXman <i.nixman@gmail.com>
X-Patchwork-Id: 123060
Return-Path: 
 <gcc-patches-return-306137-incoming=patchwork.ozlabs.org@gcc.gnu.org>
X-Original-To: incoming@patchwork.ozlabs.org
Delivered-To: patchwork-incoming@bilbo.ozlabs.org
Received: from sourceware.org (server1.sourceware.org [209.132.180.131])
	by ozlabs.org (Postfix) with SMTP id 7B78CB6F7B
	for <incoming@patchwork.ozlabs.org>;
	Tue,  1 Nov 2011 22:33:30 +1100 (EST)
Received: (qmail 26873 invoked by alias); 1 Nov 2011 11:33:23 -0000
Received: (qmail 26857 invoked by uid 22791); 1 Nov 2011 11:33:21 -0000
X-SWARE-Spam-Status: No, hits=-0.9 required=5.0	tests=AWL, BAYES_00,
	DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, FREEMAIL_FROM,
	RCVD_IN_DNSWL_LOW
X-Spam-Check-By: sourceware.org
Received: from mail-ey0-f175.google.com (HELO mail-ey0-f175.google.com)
	(209.85.215.175) by sourceware.org (qpsmtpd/0.43rc1) with
	ESMTP; Tue, 01 Nov 2011 11:33:02 +0000
Received: by eyd9 with SMTP id 9so6990148eyd.20 for <multiple recipients>;
	Tue, 01 Nov 2011 04:33:01 -0700 (PDT)
MIME-Version: 1.0
Received: by 10.213.27.135 with SMTP id i7mr302097ebc.107.1320147181311;
	Tue, 01 Nov 2011 04:33:01 -0700 (PDT)
Received: by 10.213.27.148 with HTTP; Tue, 1 Nov 2011 04:33:01 -0700 (PDT)
In-Reply-To: <0223B132-51E6-4B54-8C2D-0EC690A5E9E0@oracle.com>
References: 
 <CAMPTgK2Fph+jQBtKQ+nHa7+BMdUCu=zT3dWaUO0pc7z=Xg8mWg@mail.gmail.com>
	<0223B132-51E6-4B54-8C2D-0EC690A5E9E0@oracle.com>
Date: Tue, 1 Nov 2011 15:33:01 +0400
Message-ID: 
 <CAMPTgK0dyW0uP03vmOJ4N53vk0NwbFOgirGFqwz7wD2SFZhE_A@mail.gmail.com>
Subject: Re: implementation of std::thread::hardware_concurrency()
From: niXman <i.nixman@gmail.com>
To: gcc-patches@gcc.gnu.org, libstdc++@gcc.gnu.org
Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-patches.gcc.gnu.org>
List-Unsubscribe: 
 <mailto:gcc-patches-unsubscribe-incoming=patchwork.ozlabs.org@gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-patches/>
List-Post: <mailto:gcc-patches@gcc.gnu.org>
List-Help: <mailto:gcc-patches-help@gcc.gnu.org>
Sender: gcc-patches-owner@gcc.gnu.org
Delivered-To: mailing list gcc-patches@gcc.gnu.org

Rechecked.





2011/11/1 Paolo Carlini <pcarlini@gmail.com>:
> Hi,
>
>> This is patch is implement the std::thread::hardware_concurrency().
>> Tested on pthreads-win32/winpthreads on windows OS, and on Linux/FreeBSD.
>
> Please send library patches to the library mailing list too. Also, always parch mainline first: actually in the latter the function is alread implemented, maybe something is missing for win32, please check, rediff, and resend.
>
> Thanks
> Paolo

diff --git a/libstdc++-v3/src/thread.cc b/libstdc++-v3/src/thread.cc
index 09e7fc5..6feda4d 100644
--- a/libstdc++-v3/src/thread.cc
+++ b/libstdc++-v3/src/thread.cc
@@ -112,10 +112,20 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION
   unsigned int
   thread::hardware_concurrency() noexcept
   {
-    int __n = _GLIBCXX_NPROCS;
-    if (__n < 0)
-      __n = 0;
-    return __n;
+    int count=0;
+#if defined(PTW32_VERSION) || \
+   (defined(__MINGW64_VERSION_MAJOR) && defined(_POSIX_THREADS)) || \
+   defined(__hpux)
+    count=pthread_num_processors_np();
+#elif defined(__APPLE__) || defined(__FreeBSD__)
+    size_t size=sizeof(count);
+    sysctlbyname("hw.ncpu", &count, &size, NULL, 0);
+#elif defined(_SC_NPROCESSORS_ONLN)
+    count=sysconf(_SC_NPROCESSORS_ONLN);
+#elif defined(_GLIBCXX_USE_GET_NPROCS)
+    count=_GLIBCXX_NPROCS;
+#endif
+    return (count>0)?count:0;
   }

 _GLIBCXX_END_NAMESPACE_VERSION