Commit 7ce5b685 authored by Chris Wilson's avatar Chris Wilson

drm/i915/selftests: Use mul_u32_u32() for 32b x 32b -> 64b result

As realised by commit 9e3d6223 ("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: default avatarChris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20170913105154.2910-2-chris@chris-wilson.co.ukReviewed-by: default avatarVille Syrjälä <ville.syrjala@linux.intel.com>
parent 3123698f
...@@ -121,7 +121,7 @@ static int igt_sync(void *arg) ...@@ -121,7 +121,7 @@ static int igt_sync(void *arg)
static unsigned int random_engine(struct rnd_state *rnd) 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) static int bench_sync(void *arg)
......
...@@ -41,11 +41,6 @@ u64 i915_prandom_u64_state(struct rnd_state *rnd) ...@@ -41,11 +41,6 @@ u64 i915_prandom_u64_state(struct rnd_state *rnd)
return x; 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, void i915_random_reorder(unsigned int *order, unsigned int count,
struct rnd_state *state) struct rnd_state *state)
{ {
......
...@@ -43,6 +43,11 @@ ...@@ -43,6 +43,11 @@
u64 i915_prandom_u64_state(struct rnd_state *rnd); 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, unsigned int *i915_random_order(unsigned int count,
struct rnd_state *state); struct rnd_state *state);
void i915_random_reorder(unsigned int *order, void i915_random_reorder(unsigned int *order,
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment