From: Emil Velikov <emil.veli...@collabora.com>
If the mutexattrs are the default one can just pass NULL to
pthread_mutex_init. As the compiler does not know this detail it
unnecessarily creates/destroys the attrs.
Signed-off-by: Emil Velikov <emil.veli...@collabora.com>
---
While going through GLVND, I've noticed that it (sort of) breaks its
assumptions/goals - 'we don't want the heavy locking/etc. brought by
pthreads' [for single threaded uses]
Thus I gave mesa a quick look and the following popped up:
- pthread_once - libglapi, classic + dri
Replace with an atomic test & set combo ?
- pthread_mutexattr_* - all dri modules, libGL-apple
Using a recursive lock in src/mesa/main/shared.c and
src/glx/apple/apple_glx_drawable.c
- pthread_key_* - EGL
- pthread_.etspecific - EGL
Extend pthread-stubs explicitly required it by mesa ?
Note: the original code that pthread-stubs is based on (libX11) does
have these ;-)
- pthread_barrier_* - llvmpipe
Fall-back to the mutex + cond implementation ?
- pthread_setname_np - llvmpipe
Do we need this ? Afaict the Windows build does not have an equivalent.
- pthread_join - nine, llvmpipe, radeon(s), rbug, omx (thanks bellagio)
- pthread_create - nine, llvmpipe, radeon(s), rbug
- pthread_sigmask - nine, llvmpipe, radeon(s), rbug
These four (five inc bellagio/omx) want more than one thread. How do we
get others pthread free, while keeping these happy ?
Please let me know how you feel on the topic. Do you see this as worthy
goal ? Does the proposed solutions sound OK ? Can you think of any
alternatives?
-Emil
P.S. For anyone who wonders, libc (GNU one only iirc) provides
lightweight stubs, thus single-threaded apps work without the overhead.
---
include/c11/threads_posix.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/include/c11/threads_posix.h b/include/c11/threads_posix.h
index ce9853b..11d36e4 100644
--- a/include/c11/threads_posix.h
+++ b/include/c11/threads_posix.h
@@ -180,9 +180,14 @@ mtx_init(mtx_t *mtx, int type)
&& type != (mtx_timed|mtx_recursive)
&& type != (mtx_try|mtx_recursive))
return thrd_error;
+
+ if ((type & mtx_recursive) == 0) {
+ pthread_mutex_init(mtx, NULL);
+ return thrd_success;
+ }
+
pthread_mutexattr_init(&attr);
- if ((type & mtx_recursive) != 0)
- pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
+ pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE);
pthread_mutex_init(mtx, &attr);
pthread_mutexattr_destroy(&attr);
return thrd_success;
--
2.8.0
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/mesa-dev
