Re: [PATCH] Faster process initialization

[Christopher Faylor]

On Wed, Sep 01, 2010 at 08:16:49PM +0200, Magnus Holmgren wrote:
>This patch speeds up process initialization on 64-bit systems. Maybe
>the comment "Initialize signal processing here ..." should be re-worded
>or removed completely.

Yes, the fact that the comment makes no sense when moved would be your
first clue that it should be deleted.

>The speed difference can be noticeable.
>"while (true); do date; done | uniq -c" manages more than 3 times more
>"date" executions per second on my system.

Although you participated in the thread, you apparently ignored this:

http://cygwin.com/ml/cygwin/2010-08/msg01000.html

So, patch thoughtfully rejected.

cgf

[PATCH] Faster process initialization

[Magnus Holmgren]

This patch speeds up process initialization on 64-bit systems. Maybe
the comment "Initialize signal processing here ..." should be re-worded
or removed completely.

The speed difference can be noticeable.
"while (true); do date; done | uniq -c" manages more than 3 times more
"date" executions per second on my system.


2010-09-01  Magnus Holmgren  

* dcrt0.cc (dll_crt0_0): Remove call to sigproc_init. It creates
a thread, and execution of that thread can be delayed during
DLL init, slowing things down (seen on 64-bit systems).
(dll_crt0_1): Always call sigproc_init.


Index: src/winsup/cygwin/dcrt0.cc
===
RCS file: /cvs/src/src/winsup/cygwin/dcrt0.cc,v
retrieving revision 1.382
diff -u -p -r1.382 dcrt0.cc
--- src/winsup/cygwin/dcrt0.cc  30 Aug 2010 23:23:28 -  1.382
+++ src/winsup/cygwin/dcrt0.cc  1 Sep 2010 17:49:26 -
@@ -740,11 +740,9 @@ dll_crt0_0 ()
}
 }

-  /* Initialize signal processing here, early, in the hopes that the creation
- of a thread early in the process will cause more predictability in memory
- layout for the main thread. */
-  if (!dynamically_loaded)
-sigproc_init ();
+  /* Don't initialize signal processing here. It creates a thread, and
+ execution of threads created during DLL initialization can be
+ delayed (e.g., on 64-bit Windows Vista and Windows 7) */

   user_data->threadinterface->Init ();

@@ -789,8 +787,10 @@ dll_crt0_1 (void *)
 {
   extern void initial_setlocale ();

-  if (dynamically_loaded)
-sigproc_init ();
+  /* Initialize signal processing here, early, in the hopes that the creation
+ of a thread early in the process will cause more predictability in memory
+ layout for the main thread. */
+  sigproc_init ();
   check_sanity_and_sync (user_data);

   /* Initialize malloc and then call user_shared_initialize since it relies

--
  Magnus

[PATCH] Faster process initialization

[Magnus Holmgren]

This patch speeds up process initialization on 64-bit systems. Maybe
the comment "Initialize signal processing here ..." should be re-worded
or removed completely.

The speed difference can be noticeable.
"while (true); do date; done | uniq -c" manages more than 3 times more
"date" executions per second on my system.


2010-09-01  Magnus Holmgren  

* dcrt0.cc (dll_crt0_0): Remove call to sigproc_init. It creates
a thread, and execution of that thread can be delayed during
DLL init, slowing things down (seen on 64-bit systems).
(dll_crt0_1): Always call sigproc_init.


Index: src/winsup/cygwin/dcrt0.cc
===
RCS file: /cvs/src/src/winsup/cygwin/dcrt0.cc,v
retrieving revision 1.382
diff -u -p -r1.382 dcrt0.cc
--- src/winsup/cygwin/dcrt0.cc  30 Aug 2010 23:23:28 -  1.382
+++ src/winsup/cygwin/dcrt0.cc  1 Sep 2010 17:49:26 -
@@ -740,11 +740,9 @@ dll_crt0_0 ()
}
 }

-  /* Initialize signal processing here, early, in the hopes that the creation
- of a thread early in the process will cause more predictability in memory
- layout for the main thread. */
-  if (!dynamically_loaded)
-sigproc_init ();
+  /* Don't initialize signal processing here. It creates a thread, and
+ execution of threads created during DLL initialization can be
+ delayed (e.g., on 64-bit Windows Vista and Windows 7) */

   user_data->threadinterface->Init ();

@@ -789,8 +787,10 @@ dll_crt0_1 (void *)
 {
   extern void initial_setlocale ();

-  if (dynamically_loaded)
-sigproc_init ();
+  /* Initialize signal processing here, early, in the hopes that the creation
+ of a thread early in the process will cause more predictability in memory
+ layout for the main thread. */
+  sigproc_init ();
   check_sanity_and_sync (user_data);

   /* Initialize malloc and then call user_shared_initialize since it relies

--
  Magnus