[i-g-t] gem_wsim: Fix preempt period assert
diff mbox series

Message ID 20200427090014.10041-1-tvrtko.ursulin@linux.intel.com
State New
Headers show
Series
  • [i-g-t] gem_wsim: Fix preempt period assert
Related show

Commit Message

Tvrtko Ursulin April 27, 2020, 9 a.m. UTC
From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

Recently added assert in a common helper used for calculating batch
duration and preemption period is harmful when preemption is disabled on a
context. Split out into low level and high level helper and use the former
for preemption period queries.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
 benchmarks/gem_wsim.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

Comments

Chris Wilson April 27, 2020, 9:05 a.m. UTC | #1
Quoting Tvrtko Ursulin (2020-04-27 10:00:14)
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> 
> Recently added assert in a common helper used for calculating batch
> duration and preemption period is harmful when preemption is disabled on a
> context. Split out into low level and high level helper and use the former
> for preemption period queries.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
>  benchmarks/gem_wsim.c | 15 ++++++++++++---
>  1 file changed, 12 insertions(+), 3 deletions(-)
> 
> diff --git a/benchmarks/gem_wsim.c b/benchmarks/gem_wsim.c
> index 81f47b86d619..ad4edb936920 100644
> --- a/benchmarks/gem_wsim.c
> +++ b/benchmarks/gem_wsim.c
> @@ -1151,7 +1151,7 @@ __get_ctx(struct workload *wrk, const struct w_step *w)
>  }
>  
>  static unsigned long
> -get_bb_sz(const struct w_step *w, unsigned int duration)
> +__get_bb_sz(const struct w_step *w, unsigned int duration)
>  {
>         enum intel_engine_id engine = w->engine;
>         struct ctx *ctx = __get_ctx(w->wrk, w);
> @@ -1165,6 +1165,15 @@ get_bb_sz(const struct w_step *w, unsigned int duration)
>         d = ALIGN(duration * engine_calib_map[engine] * sizeof(uint32_t) /
>                   nop_calibration_us,
>                   sizeof(uint32_t));

Preempt disabled == w->preempt_us = 0 => duration = 0.

Ok, that follows that d is expected to be 0. And the caller expands to
at least a page.

Not really convinced the assert is worth it, but
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
-Chris

Patch
diff mbox series

diff --git a/benchmarks/gem_wsim.c b/benchmarks/gem_wsim.c
index 81f47b86d619..ad4edb936920 100644
--- a/benchmarks/gem_wsim.c
+++ b/benchmarks/gem_wsim.c
@@ -1151,7 +1151,7 @@  __get_ctx(struct workload *wrk, const struct w_step *w)
 }
 
 static unsigned long
-get_bb_sz(const struct w_step *w, unsigned int duration)
+__get_bb_sz(const struct w_step *w, unsigned int duration)
 {
 	enum intel_engine_id engine = w->engine;
 	struct ctx *ctx = __get_ctx(w->wrk, w);
@@ -1165,6 +1165,15 @@  get_bb_sz(const struct w_step *w, unsigned int duration)
 	d = ALIGN(duration * engine_calib_map[engine] * sizeof(uint32_t) /
 		  nop_calibration_us,
 		  sizeof(uint32_t));
+
+	return d;
+}
+
+static unsigned long
+get_bb_sz(const struct w_step *w, unsigned int duration)
+{
+	unsigned long d = __get_bb_sz(w, duration);
+
 	igt_assert(d);
 
 	return d;
@@ -1174,7 +1183,7 @@  static void
 init_bb(struct w_step *w, unsigned int flags)
 {
 	const unsigned int arb_period =
-			get_bb_sz(w, w->preempt_us) / sizeof(uint32_t);
+			__get_bb_sz(w, w->preempt_us) / sizeof(uint32_t);
 	const unsigned int mmap_len = ALIGN(w->bb_sz, 4096);
 	unsigned int i;
 	uint32_t *ptr;
@@ -1395,7 +1404,7 @@  alloc_step_batch(struct workload *wrk, struct w_step *w, unsigned int flags)
 
 	if (w->unbound_duration)
 		/* nops + MI_ARB_CHK + MI_BATCH_BUFFER_START */
-		w->bb_sz = max(PAGE_SIZE, get_bb_sz(w, w->preempt_us)) +
+		w->bb_sz = max(PAGE_SIZE, __get_bb_sz(w, w->preempt_us)) +
 			   (1 + 3) * sizeof(uint32_t);
 	else
 		w->bb_sz = get_bb_sz(w, w->duration.max);