benchmarks/gem_exec_trace: Mark the mmap as sequentially read

Use madvise(MADV_SEQUENTIAL) to let the kernel optimise for our
straightforward sequential read pattern.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

1 files changed, 5 insertions, 0 deletions

diff --git a/benchmarks/gem_exec_trace.c b/benchmarks/gem_exec_trace.c
index 598527ce..398fdaec 100644
--- a/benchmarks/gem_exec_trace.c
+++ b/benchmarks/gem_exec_trace.c
@@ -225,6 +225,11 @@ static void replay(const char *filename)
 	ptr = mmap(0, st.st_size, PROT_READ, MAP_SHARED, fd, 0);
 	close(fd);
 
+	if (ptr == MAP_FAILED)
+		return;
+
+	madvise(ptr, st.st_size, MADV_SEQUENTIAL);
+
 	end = ptr + st.st_size;
 	fd = drm_open_any();