[PATH i-g-t 07/13] gem_wsim: Make batches preemptable by default

Tvrtko Ursulin
2018-09-05T13:49:52Z

MI_NOOP cannot be preempted which means up to now gem_wsim workloads were
preemptable on batch buffer granularity only.

Add MI_ARB_CHK every 100us so the new default is mid-batch preemption.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
---
benchmarks/gem_wsim.c | 20 ++++++++++++++++++++
1 file changed, 20 insertions(+)

diff --git a/benchmarks/gem_wsim.c b/benchmarks/gem_wsim.c
index 0c52ec567430..7f2d0c83a0e7 100644
--- a/benchmarks/gem_wsim.c
+++ b/benchmarks/gem_wsim.c
@@ -685,6 +685,25 @@ static unsigned long get_bb_sz(unsigned int duration)
nop_calibration_us, sizeof(uint32_t));
}

+static void
+init_bb(struct w_step *w, unsigned int flags)
+{
+ /* Preemption point every 100us. */
+ const unsigned int arb_period = get_bb_sz(100) / sizeof(uint32_t);
+ unsigned int i;
+ uint32_t *ptr;
+
+ gem_set_domain(fd, w->bb_handle,
+ I915_GEM_DOMAIN_WC, I915_GEM_DOMAIN_WC);
+
+ ptr = gem_mmap__wc(fd, w->bb_handle, 0, w->bb_sz, PROT_WRITE);
+
+ for (i = arb_period; i < w->bb_sz / sizeof(uint32_t); i += arb_period)
+ ptr[i] = 0x5 << 23; /* MI_ARB_CHK */
+
+ munmap(ptr, w->bb_sz);
+}
+
static void
terminate_bb(struct w_step *w, unsigned int flags)
{
@@ -839,6 +858,7 @@ alloc_step_batch(struct workload *wrk, struct w_step *w, unsigned int flags)

w->bb_sz = get_bb_sz(w->duration.max);
w->bb_handle = w->obj[j].handle = gem_create(fd, w->bb_sz);
+ init_bb(w, flags);
terminate_bb(w, flags);

if (flags & SEQNO) {