The Arm backend sets the default sched-pressure algorithm to
SCHED_PRESSURE_MODEL. Benchmarking on AArch64 shows this
speeds up floating point performance on SPEC - eg. CactusBSSN improves
by ~16%. The gains are mostly due to less spilling, so enable this on AArch64
by default.
OK for commit?
2017-11-02 Wilco Dijkstra <wdijk...@arm.com>
* config/aarch64/aarch64.c (aarch64_override_options_internal):
Set PARAM_SCHED_PRESSURE_ALGORITHM to SCHED_PRESSURE_MODEL.
--
diff --git a/gcc/config/aarch64/aarch64.c b/gcc/config/aarch64/aarch64.c
index
34456e96497ac7b6d2f9931187ff05619e1934a4..750b0bc29c0963742d5d7bb4ae4619d93bec3e4a
100644
--- a/gcc/config/aarch64/aarch64.c
+++ b/gcc/config/aarch64/aarch64.c
@@ -9276,6 +9276,11 @@ aarch64_override_options_internal (struct gcc_options
*opts)
opts->x_param_values,
global_options_set.x_param_values);
+ /* Use the alternative scheduling-pressure algorithm by default. */
+ maybe_set_param_value (PARAM_SCHED_PRESSURE_ALGORITHM, SCHED_PRESSURE_MODEL,
+ opts->x_param_values,
+ global_options_set.x_param_values);
+
/* Enable sw prefetching at specified optimization level for
CPUS that have prefetch. Lower optimization level threshold by 1
when profiling is enabled. */
