Re: Suggestions for improving gcc 3.2 compilation speed?

["Kaveh R. Ghazi" <ghazi at caip dot rutgers dot edu>]

 > I've been running gcc 2.95.3 on a 1Ghz/512MB RAM PC running RedHat
 > 7.2. It takes 20 minutes to compile my application, so I recently got
 > a new computer to reduce the time I wait for compiles. This new
 > computer is a 2.8 Ghz CPU/1GB RAM running RedHat 8.0. Since RedHat 8.0
 > comes with gcc 3.2 I figured I'd give it a try. It takes 20 minutes to
 > compile my application. (!!!)
 > 
 > I'm a little frustrated that the compilation speed is so slow with gcc
 > 3.2, especially since this is a commercial application (i.e., this is
 > my job). Is there anything I can do to improve the compilation speed?
 > Will newer gcc releases be as fast as gcc 2.95.3 (or faster)? Or is my
 > best bet to stick with 2.95.3?

With 1GB of RAM, try this patch it might help some.  But on machines
with less memory it may cause thrashing, so it's not a general
solution.

I'd appreciate hearing from you what effect it has.

		Thanks,
		--Kaveh

PS: What language is your app written in?


diff -rup orig/egcc-3.2-CVS20030223/gcc/ggc-page.c egcc-3.2-CVS20030223/gcc/ggc-page.c
--- orig/egcc-3.2-CVS20030223/gcc/ggc-page.c	2002-01-05 17:11:21.000000000 -0500
+++ egcc-3.2-CVS20030223/gcc/ggc-page.c	2003-02-23 19:13:27.726803129 -0500
@@ -344,11 +344,11 @@ static struct globals
    this factor times the allocation at the end of the last collection.
    In other words, total allocation must expand by (this factor minus
    one) before collection is performed.  */
-#define GGC_MIN_EXPAND_FOR_GC (1.3)
+#define GGC_MIN_EXPAND_FOR_GC (2.0)
 
 /* Bound `allocated_last_gc' to 4MB, to prevent the memory expansion
    test from triggering too often when the heap is small.  */
-#define GGC_MIN_LAST_ALLOCATED (4 * 1024 * 1024)
+#define GGC_MIN_LAST_ALLOCATED (128 * 1024 * 1024)
 
 /* Allocate pages in chunks of this size, to throttle calls to memory
    allocation routines.  The first page is used, the rest go onto the