From 55d78a4dcf3876910155e541bf7202aa8a082d28 Mon Sep 17 00:00:00 2001
From: John Cupitt <jcupitt@gmail.com>
Date: Mon, 15 Mar 2010 18:11:36 +0000
Subject: [PATCH] stuff

---
 ChangeLog                     |  2 ++
 TODO                          |  6 ------
 configure.in                  |  2 +-
 libvips/iofuncs/threadgroup.c | 29 ++++++++++++++++++++++++-----
 4 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index 0ea4c39d..e7dbc8c2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -32,6 +32,8 @@
 - im_render() mask image generation no longer triggers image calc
 - threadgroups scale output buffers with number of threads for smalltile ...
   improves SMP scaling for narrow images on many-way machines
+- default to max number of processors (--vips-concurrency and IM_CONCURRENCY
+  set >0 can override) on linux and win32
 
 15/1/10 started 7.21.1
 - added "written" callbacks, used to implement write to non-vips formats
diff --git a/TODO b/TODO
index 77a573c7..0f94d31e 100644
--- a/TODO
+++ b/TODO
@@ -1,9 +1,3 @@
-- try
-
-	vips im_rot90 babe.jpg test2.v
-
-  wtf, thinstrip output o.O
-
 - doing im_create_fmask() and friends
 
 - how about im_invalidate_area()? we currently repaint the whole window on
diff --git a/configure.in b/configure.in
index 4351aa7c..b6351ae1 100644
--- a/configure.in
+++ b/configure.in
@@ -213,7 +213,7 @@ AC_TYPE_SIZE_T
 AC_FUNC_MEMCMP
 AC_FUNC_MMAP
 AC_FUNC_VPRINTF
-AC_CHECK_FUNCS([getcwd gettimeofday getwd memset munmap putenv realpath strcasecmp strchr strcspn strdup strerror strrchr strspn vsnprintf realpath mkstemp mktemp random rand])
+AC_CHECK_FUNCS([getcwd gettimeofday getwd memset munmap putenv realpath strcasecmp strchr strcspn strdup strerror strrchr strspn vsnprintf realpath mkstemp mktemp random rand sysconf])
 AC_CHECK_LIB(m,cbrt,[AC_DEFINE(HAVE_CBRT,1,[have cbrt() in libm.])])
 AC_CHECK_LIB(m,hypot,[AC_DEFINE(HAVE_HYPOT,1,[have hypot() in libm.])])
 
diff --git a/libvips/iofuncs/threadgroup.c b/libvips/iofuncs/threadgroup.c
index 0edb8a32..9cea5f0f 100644
--- a/libvips/iofuncs/threadgroup.c
+++ b/libvips/iofuncs/threadgroup.c
@@ -146,17 +146,32 @@ im_concurrency_get( void )
 {
 	const char *str;
 	int nthr;
+	int x;
 
 	/* Tell the threads system how much concurrency we expect.
 	 */
 	if( im__concurrency > 0 )
 		nthr = im__concurrency;
-	else if( (str = g_getenv( IM_CONCURRENCY )) ) 
-		nthr = atoi( str );
-	else
-		/* Stick to minimum.
-		 */
+	else if( (str = g_getenv( IM_CONCURRENCY )) && 
+		(x = atoi( str )) > 0 )
+		nthr = x;
+	else {
 		nthr = 1;
+#ifdef HAVE_SYSCONF
+{
+		x = sysconf( _SC_NPROCESSORS_ONLN );
+		if( x > 0 )
+			nthr = x;
+}
+#endif /*HAVE_SYSCONF*/
+#ifdef OS_WIN32
+		SYSTEM_INFO si;
+
+		GetSystemInfo( &si );
+
+		nthr = si.dwNumberOfProcessors;
+#endif /*OS_WIN32*/
+	}
 
 	if( nthr < 1 || nthr > IM_MAX_THREADS ) {
 		nthr = IM_CLIP( 1, nthr, IM_MAX_THREADS );
@@ -165,6 +180,10 @@ im_concurrency_get( void )
 			_( "threads clipped to %d" ), nthr );
 	}
 
+	/* Save for next time around.
+	 */
+	im_concurrency_set( nthr );
+
 	/* 
 
 		FIXME .. hmm