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| author | Chris Wilson <chris@chris-wilson.co.uk> | 2017-09-13 11:51:54 +0100 |
|---|---|---|
| committer | Chris Wilson <chris@chris-wilson.co.uk> | 2017-09-13 13:27:20 +0100 |
| commit | 7ce5b6850b47824a2b8d0a17b5fe75f9942e5cd1 (patch) | |
| tree | 519363302f8b9d6ebd65278975a48ddb99ce6e99 | |
| parent | 3123698f50fe4ac9ddb775dcd2b34a1d9cdd603f (diff) | |
| download | linux-7ce5b6850b47824a2b8d0a17b5fe75f9942e5cd1.tar.bz2 | |
drm/i915/selftests: Use mul_u32_u32() for 32b x 32b -> 64b result
As realised by commit 9e3d6223d209 ("math64, timers: Fix 32bit
mul_u64_u32_shr() and friends"), GCC does not always generate ideal code
for performing a 32b x 32b multiply returning a 64b result (i.e. where
we idiomatically use u64 result = (u64)x * (u32)x).
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20170913105154.2910-2-chris@chris-wilson.co.uk
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
| -rw-r--r-- | drivers/gpu/drm/i915/selftests/i915_gem_timeline.c | 2 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/selftests/i915_random.c | 5 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/selftests/i915_random.h | 5 |
3 files changed, 6 insertions, 6 deletions
diff --git a/drivers/gpu/drm/i915/selftests/i915_gem_timeline.c b/drivers/gpu/drm/i915/selftests/i915_gem_timeline.c index 7a44dab631b8..4795877abe56 100644 --- a/drivers/gpu/drm/i915/selftests/i915_gem_timeline.c +++ b/drivers/gpu/drm/i915/selftests/i915_gem_timeline.c @@ -121,7 +121,7 @@ out: static unsigned int random_engine(struct rnd_state *rnd) { - return ((u64)prandom_u32_state(rnd) * I915_NUM_ENGINES) >> 32; + return i915_prandom_u32_max_state(I915_NUM_ENGINES, rnd); } static int bench_sync(void *arg) diff --git a/drivers/gpu/drm/i915/selftests/i915_random.c b/drivers/gpu/drm/i915/selftests/i915_random.c index d044bf9a6feb..ea0f5dbc0eb7 100644 --- a/drivers/gpu/drm/i915/selftests/i915_random.c +++ b/drivers/gpu/drm/i915/selftests/i915_random.c @@ -41,11 +41,6 @@ u64 i915_prandom_u64_state(struct rnd_state *rnd) return x; } -static inline u32 i915_prandom_u32_max_state(u32 ep_ro, struct rnd_state *state) -{ - return upper_32_bits((u64)prandom_u32_state(state) * ep_ro); -} - void i915_random_reorder(unsigned int *order, unsigned int count, struct rnd_state *state) { diff --git a/drivers/gpu/drm/i915/selftests/i915_random.h b/drivers/gpu/drm/i915/selftests/i915_random.h index 6c9379871384..7dffedc501ca 100644 --- a/drivers/gpu/drm/i915/selftests/i915_random.h +++ b/drivers/gpu/drm/i915/selftests/i915_random.h @@ -43,6 +43,11 @@ u64 i915_prandom_u64_state(struct rnd_state *rnd); +static inline u32 i915_prandom_u32_max_state(u32 ep_ro, struct rnd_state *state) +{ + return upper_32_bits(mul_u32_u32(prandom_u32_state(state), ep_ro)); +} + unsigned int *i915_random_order(unsigned int count, struct rnd_state *state); void i915_random_reorder(unsigned int *order, |