On 08/06/2015 06:10 PM, Matt Turner wrote:
Patches 1-11 improve performance of SynMark OglBatch7 by 6.29586% +/- 0.277734%
(n=337) and OglMultithread by 1.12564% +/- 0.424038% (n=209). I haven't
benchmarked individual patches because I'd like to not waste all that time if I
get review feedback that requires me to change things. :)
Patches 12-13 were supposed to improve performance, but seem to make an
existing thread-safety problem worse, so I'm not proposing them for inclusion.
[01/13] c11/threads: Assert that mtx is non-NULL and check
[02/13] mesa: Remove debugging code from _mesa_reference_*.
[03/13] mesa: Add locking to sampler objects.
[04/13] mesa: Add locking to programs.
These two add missing locks to sampler and program objects, which
I believe are supposed to be thread-safe.
[05/13] mesa: Replace buffer object locks with atomic inc/dec.
[06/13] mesa: Replace sampler object locks with atomic inc/dec.
[07/13] mesa: Replace program locks with atomic inc/dec.
[08/13] mesa: Replace renderbuffer object locks with atomic inc/dec.
[09/13] mesa: Replace texture buffer object locks with atomic inc/dec.
These five replace locks around RefCount++/-- with atomic increment
and decrement.
[10/13] hash: Add _mesa_HashRemoveLocked() function.
[11/13] mesa: Replace uses of Shared->Mutex with hash-table mutexes
These two replace uses of ctx->Shared->Mutex with the mutexes in the
hash tables.
1-13 look good to me, just a minor nit on #10.
I'd be OK w/ squashing 3 & 6, and 4 & 7, but not a big deal.
For the series,
Reviewed-by: Brian Paul <bri...@vmware.com>
[12/13] mesa: Remove unnecessary locking from container
[13/13] mesa: Remove deleteFlag pattern.
*I am not proposing these for inclusion*
These two remove some "unnecessary" locking from so called "container
objects" that are not shared between threads by the GL. While I expected
them to improve performance, they actually cause double-free errors in
SynMark OglMultithread. Valgrind's helgrind tool shows that there are many
thread-safety issues in the texture code, and removing these locks seems to
exacerbate the problem.
Specifically, multiple threads are reading and writing to gl_texture_objects
without any synchronization from places like intel_finalize_mipmap_tree(),
gen7_update_texture_surface(), brw_populate_sampler_prog_key_data(),
update_sampler_state(), and _mesa_BindTexture().
Suggestions for solving this (apparently quite longstanding) problem are
welcome.
gl_texture_object appears all over the place. Adding locking everywhere
could be a nightmare but I'm not sure what other solution there is off-hand.
-Brian
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