* [PATCH 4/8] Disable max_issue when scheduling for register pressure
@ 2014-10-21 3:31 Maxim Kuvyrkov
2014-10-21 15:57 ` Vladimir Makarov
0 siblings, 1 reply; 2+ messages in thread
From: Maxim Kuvyrkov @ 2014-10-21 3:31 UTC (permalink / raw)
To: GCC Patches; +Cc: Vladimir Makarov, Jeff Law, ramrad01
[-- Attachment #1: Type: text/plain, Size: 634 bytes --]
Hi,
This patch disables max_issue-based lookahead multipass scheduling when register-pressure heuristics are active. The two approaches tend to undo each others decisions and don't play well together.
Currently this patch is a no-op, since no target uses both max_issue and register-pressure scheduling. This will change soon with upcoming patches that will enable max_issue during 2nd scheduling pass for ARM and AArch64.
Bootstrapped on x86_64-linux-gnu. Regression testing is in progress. OK to commit if no regressions?
[ChangeLog is part of the git patch]
Thank you,
--
Maxim Kuvyrkov
www.linaro.org
[-- Attachment #2: 0004-Disable-max_issue-when-scheduling-for-register-press.patch --]
[-- Type: application/octet-stream, Size: 1071 bytes --]
From caae8fd31b92ea63d91604df4d71a7866303ec2a Mon Sep 17 00:00:00 2001
From: Maxim Kuvyrkov <maxim.kuvyrkov@linaro.org>
Date: Tue, 21 Oct 2014 00:25:11 +0100
Subject: [PATCH 4/8] Disable max_issue when scheduling for register pressure
* haifa-sched.c (sched_init): Disable max_issue when scheduling for
register pressure.
---
gcc/haifa-sched.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/gcc/haifa-sched.c b/gcc/haifa-sched.c
index 4f9648c..26d9e29 100644
--- a/gcc/haifa-sched.c
+++ b/gcc/haifa-sched.c
@@ -6867,7 +6867,10 @@ sched_init (void)
else
issue_rate = 1;
- if (targetm.sched.first_cycle_multipass_dfa_lookahead)
+ if (targetm.sched.first_cycle_multipass_dfa_lookahead
+ /* Don't use max_issue with reg_pressure scheduling. Multipass
+ scheduling and reg_pressure scheduling undo each other's decisions. */
+ && sched_pressure == SCHED_PRESSURE_NONE)
dfa_lookahead = targetm.sched.first_cycle_multipass_dfa_lookahead ();
else
dfa_lookahead = 0;
--
1.7.9.5
^ permalink raw reply [flat|nested] 2+ messages in thread
* Re: [PATCH 4/8] Disable max_issue when scheduling for register pressure
2014-10-21 3:31 [PATCH 4/8] Disable max_issue when scheduling for register pressure Maxim Kuvyrkov
@ 2014-10-21 15:57 ` Vladimir Makarov
0 siblings, 0 replies; 2+ messages in thread
From: Vladimir Makarov @ 2014-10-21 15:57 UTC (permalink / raw)
To: Maxim Kuvyrkov, GCC Patches; +Cc: Jeff Law, ramrad01
On 10/20/2014 11:21 PM, Maxim Kuvyrkov wrote:
> Hi,
>
> This patch disables max_issue-based lookahead multipass scheduling when register-pressure heuristics are active. The two approaches tend to undo each others decisions and don't play well together.
Yes, I am agree.
> Currently this patch is a no-op, since no target uses both max_issue and register-pressure scheduling. This will change soon with upcoming patches that will enable max_issue during 2nd scheduling pass for ARM and AArch64.
>
> Bootstrapped on x86_64-linux-gnu. Regression testing is in progress. OK to commit if no regressions?
>
The patch is ok. Thanks, Maxim.
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2014-10-21 15:55 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2014-10-21 3:31 [PATCH 4/8] Disable max_issue when scheduling for register pressure Maxim Kuvyrkov
2014-10-21 15:57 ` Vladimir Makarov
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).