From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: GCC Patches <gcc-patches@gcc.gnu.org>
Cc: Kyrylo Tkachov <Kyrylo.Tkachov@arm.com>,
Richard Earnshaw <Richard.Earnshaw@arm.com>
Subject: Re: [PATCH][Arm] Only enable fsched-pressure with Ofast
Date: Tue, 19 Nov 2019 15:17:00 -0000 [thread overview]
Message-ID: <VI1PR0801MB2127416FA7FC654EBAB2BC11834C0@VI1PR0801MB2127.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <VI1PR0801MB2127EEC02439EC8C20C44BA883790@VI1PR0801MB2127.eurprd08.prod.outlook.com>
ping
The current pressure scheduler doesn't appear to correctly track register
pressure and avoid creating unnecessary spills when register pressure is high.
As a result disabling the early scheduler improves integer performance
considerably and reduces codesize as a bonus. Since scheduling floating point
code is generally beneficial (more registers and higher latencies), only enable
the pressure scheduler with -Ofast.
On Cortex-A57 this gives a 0.7% performance gain on SPECINT2006 as well
as a 0.2% codesize reduction.
Bootstrapped on armhf. OK for commit?
ChangeLog:
2019-11-06 Wilco Dijkstra <wdijkstr@arm.com>
* gcc/common/config/arm-common.c (arm_option_optimization_table):
Enable fsched_pressure with Ofast only.
--
diff --git a/gcc/common/config/arm/arm-common.c b/gcc/common/config/arm/arm-common.c
index 41a920f6dc96833e778faa8dbcc19beac483734c..b761d3abd670a144a593c4b410b1e7fbdcb52f56 100644
--- a/gcc/common/config/arm/arm-common.c
+++ b/gcc/common/config/arm/arm-common.c
@@ -38,7 +38,7 @@ static const struct default_options arm_option_optimization_table[] =
{
/* Enable section anchors by default at -O1 or higher. */
{ OPT_LEVELS_1_PLUS, OPT_fsection_anchors, NULL, 1 },
- { OPT_LEVELS_1_PLUS, OPT_fsched_pressure, NULL, 1 },
+ { OPT_LEVELS_FAST, OPT_fsched_pressure, NULL, 1 },
{ OPT_LEVELS_NONE, 0, NULL, 0 }
};
next prev parent reply other threads:[~2019-11-19 15:12 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-06 13:57 Wilco Dijkstra
2019-11-19 15:17 ` Wilco Dijkstra [this message]
2020-01-16 19:43 ` Wilco Dijkstra
2020-02-04 10:52 ` Wilco Dijkstra
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