On Gfx4 and Gfx5, sel.l (for min) and sel.ge (for max) are implemented
using a separte cmpn and sel instruction. This lowering occurs in
fs_vistor::lower_minmax which is called very, very late... a long, long
time after the first calls to opt_cmod_propagation. As a result,
conditional modifiers can be incorrectly propagated across sel.cond on
those platforms.
No tests were affected by this change, and I find that quite shocking.
After just changing flags_written(), all of the atan tests started
failing on ILK. That required the change in cmod_propagatin (and the
addition of the prop_across_into_sel_gfx5 unit test).
Shader-db results for ILK and GM45 are below. I looked at a couple
before and after shaders... and every case that I looked at had
experienced incorrect cmod propagation. This affected a LOT of apps!
Euro Truck Simulator 2, The Talos Principle, Serious Sam 3, Sanctum 2,
Gang Beasts, and on and on... :(
I discovered this bug while working on a couple new optimization
passes. One of the passes attempts to remove condition modifiers that
are never used. The pass made no progress except on ILK and GM45.
After investigating a couple of the affected shaders, I noticed that
the code in those shaders looked wrong... investigation led to this
cause.
v2: Trivial changes in the unit tests.
v3: Fix type in comment in unit tests. Noticed by Jason and Priit.
v4: Tweak handling of BRW_OPCODE_SEL special case. Suggested by Jason.
Fixes: df1aec763e ("i965/fs: Define methods to calculate the flag subset read or written by an fs_inst.")
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Tested-by: Dave Airlie <airlied@redhat.com>
Iron Lake
total instructions in shared programs: 8180493 -> 8181781 (0.02%)
instructions in affected programs: 541796 -> 543084 (0.24%)
helped: 28
HURT: 1158
helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1
helped stats (rel) min: 0.35% max: 0.86% x̄: 0.53% x̃: 0.50%
HURT stats (abs) min: 1 max: 3 x̄: 1.14 x̃: 1
HURT stats (rel) min: 0.12% max: 4.00% x̄: 0.37% x̃: 0.23%
95% mean confidence interval for instructions value: 1.06 1.11
95% mean confidence interval for instructions %-change: 0.31% 0.38%
Instructions are HURT.
total cycles in shared programs: 239420470 -> 239421690 (<.01%)
cycles in affected programs: 2925992 -> 2927212 (0.04%)
helped: 49
HURT: 157
helped stats (abs) min: 2 max: 284 x̄: 62.69 x̃: 70
helped stats (rel) min: 0.04% max: 6.20% x̄: 1.68% x̃: 1.96%
HURT stats (abs) min: 2 max: 48 x̄: 27.34 x̃: 24
HURT stats (rel) min: 0.02% max: 2.91% x̄: 0.31% x̃: 0.20%
95% mean confidence interval for cycles value: -0.80 12.64
95% mean confidence interval for cycles %-change: -0.31% <.01%
Inconclusive result (value mean confidence interval includes 0).
GM45
total instructions in shared programs: 4985517 -> 4986207 (0.01%)
instructions in affected programs: 306935 -> 307625 (0.22%)
helped: 14
HURT: 625
helped stats (abs) min: 1 max: 1 x̄: 1.00 x̃: 1
helped stats (rel) min: 0.35% max: 0.82% x̄: 0.52% x̃: 0.49%
HURT stats (abs) min: 1 max: 3 x̄: 1.13 x̃: 1
HURT stats (rel) min: 0.12% max: 3.90% x̄: 0.34% x̃: 0.22%
95% mean confidence interval for instructions value: 1.04 1.12
95% mean confidence interval for instructions %-change: 0.29% 0.36%
Instructions are HURT.
total cycles in shared programs: 153827268 -> 153828052 (<.01%)
cycles in affected programs: 1669290 -> 1670074 (0.05%)
helped: 24
HURT: 84
helped stats (abs) min: 2 max: 232 x̄: 64.33 x̃: 67
helped stats (rel) min: 0.04% max: 4.62% x̄: 1.60% x̃: 1.94%
HURT stats (abs) min: 2 max: 48 x̄: 27.71 x̃: 24
HURT stats (rel) min: 0.02% max: 2.66% x̄: 0.34% x̃: 0.14%
95% mean confidence interval for cycles value: -1.94 16.46
95% mean confidence interval for cycles %-change: -0.29% 0.11%
Inconclusive result (value mean confidence interval includes 0).
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12191>
There are two problems with the current architecture.
In OpenGL, the id is supposed to be a unique identifier for a particular
log source. This is done so that applications can (theoretically)
filter particular log messages. The debug callback infrastructure in
Mesa assigns a uniqe value when a value of 0 is passed in. This causes
the id to get set once to a unique value for each message.
By passing a stack variable that is initialized to 0 on every call,
every time the same message is logged, it will have a different id.
This isn't great, but it's also not catastrophic.
When threaded shader compiles are used, the id *pointer* is saved and
dereferenced at a possibly much later time on a possibly different
thread. This causes one thread to access the stack from a different
thread... and that stack frame might not be valid any more. :(
I have not observed any crashes related to this particular issue.
Reviewed-by: Matt Turner <mattst88@gmail.com>
Reviewed-by: Anuj Phogat <anuj.phogat@gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12136>
This is distinct form max_cs_threads because it also encodes
restrictions about the way we use GPGPU/COMPUTE_WALKER. This gets rid
of the MIN2(64, devinfo->max_cs_threads) we have scattered all over the
driver and puts it in a central place.
Reviewed-by: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11861>
Bspec programming note metions that "Atomic messages are always forced
to "un-cacheable" in the L1 cache". We can make the L1 cache
un-cacheable and L3 with write-back policy.
v2: (Sagar Ghuge):
- Fix caching policy for atomic messages
- Fix simd exec size
v3: (Sagar Ghuge):
- Add atomic messages to brw_schedule_instructions
v4: (Jason Ekstrand):
- Rebase on lsc_msg_desc reworks
Co-authored-by: Sagar Ghuge <sagar.ghuge@intel.com>
Co-authored-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11600>
This puts the basic infrastructure in place for lowering logical
dataport messages to LSC messages. We start with the two most obvious
opcodes and add more in later patches.
v2 (Sagar Ghuge):
- Pass required params to message desc
- Remove duplicate mlen calculation
- Change commit message.
v3 (Jason Ekstrand):
- Drop TGM support
Co-authored-by: Jason Ekstrand <mark.a.janes@intel.com>
Reviewed-by: Jason Ekstrand <jason@jlekstrand.net>
Reviewed-by: Sagar Ghuge <sagar.ghuge@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/11600>
Instead of depending on the driver to compile each resume shader
separately, we compile them all in one go in the back-end and build an
SBT as part of the shader program. Shader relocs are used to make the
entries in the SBT point point to the correct resume shader.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/8637>
Unfortunately the funky Align1 regions used by the code generator in
order to implement derivatives efficiently aren't available to the
floating-point pipeline on XeHP. We need to lower them into a number
of pipelined integer shuffle instructions followed by the
floating-point difference computation.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10000>
The regioning mode used here is no longer supported by the
floating-point pipeline. We could run the regioning lowering pass in
order to fix it with some extra copies, but it's more efficient to
change the instruction to use integer types.
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10000>
