From: Jan Hubicka <hubicka@ucw.cz>
Date: Wed, 3 Sep 2025 15:45:02 +0000 (+0200)
Subject: Increase default number of LTO partitions
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=7e2fdee3e29019b10251d85880053170154776de;p=thirdparty%2Fgcc.git

Increase default number of LTO partitions

The number of LTO partitions should exceed number of CPUs (or hyper-threads) of
commonly used CPUs.  I think it is time to increase it again and as discussed
in the LTO and toplevel asm thread, doing so scales quite well. Tmp file usage
grows from 2.7 to 2.9MB which seems acceptable.  Overall build time on machine
with 256 hyperthreads is comparable.

Bootstrapped/regtested x86_64-linux, comitted.

gcc/ChangeLog:

	* params.opt (-param=lto-partitions=): INcrease default value from 128 to 512.
---

diff --git a/gcc/params.opt b/gcc/params.opt
index ac1b2c7eb26..dd53d830895 100644
--- a/gcc/params.opt
+++ b/gcc/params.opt
@@ -462,7 +462,7 @@ Common Joined UInteger Var(param_min_partition_size) Init(10000) Param
 Minimal size of a partition for LTO (in estimated instructions).
 
 -param=lto-partitions=
-Common Joined UInteger Var(param_lto_partitions) Init(128) IntegerRange(1, 65536) Param
+Common Joined UInteger Var(param_lto_partitions) Init(512) IntegerRange(1, 65536) Param
 Number of partitions the program should be split to.
 
 Enum