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A recent patch increased GCC's memory consumption!


Hi,

I am a friendly script caring about memory consumption in GCC.  Please
contact jh@suse.cz if something is going wrong.

Comparing memory consumption on compilation of combine.i, insn-attrtab.i,
and generate-3.4.ii I got:


comparing combine.c compilation at -O0 level:
    Overall memory needed: 24841k
    Peak memory use before GGC: 9590k
    Peak memory use after GGC: 8937k
    Maximum of released memory in single GGC run: 2737k
    Garbage: 40070k
    Leak: 6698k
    Overhead: 5787k
    GGC runs: 316

comparing combine.c compilation at -O1 level:
    Overall memory needed: 26812k
    Peak memory use before GGC: 17359k
    Peak memory use after GGC: 17173k
    Maximum of released memory in single GGC run: 2373k
    Garbage: 60344k
    Leak: 7084k
    Overhead: 7591k
    GGC runs: 385

comparing combine.c compilation at -O2 level:
    Overall memory needed: 26812k
    Peak memory use before GGC: 17361k
    Peak memory use after GGC: 17173k
    Maximum of released memory in single GGC run: 2456k
    Garbage: 77890k
    Leak: 7476k
    Overhead: 10123k
    GGC runs: 456

comparing combine.c compilation at -O3 level:
    Overall memory needed: 26812k
    Peak memory use before GGC: 18479k
    Peak memory use after GGC: 18109k
    Maximum of released memory in single GGC run: 3367k
    Garbage: 111044k
    Leak: 7548k
    Overhead: 13950k
    GGC runs: 515

comparing insn-attrtab.c compilation at -O0 level:
    Overall memory needed: 80920k
    Peak memory use before GGC: 69464k
    Peak memory use after GGC: 45002k
    Maximum of released memory in single GGC run: 36248k
    Garbage: 146330k
    Leak: 10091k
    Overhead: 19790k
    GGC runs: 250

comparing insn-attrtab.c compilation at -O1 level:
    Overall memory needed: 112284k
    Peak memory use before GGC: 94162k
    Peak memory use after GGC: 83709k
    Maximum of released memory in single GGC run: 32587k
    Garbage: 290093k
    Leak: 10077k
    Overhead: 36723k
    GGC runs: 245

comparing insn-attrtab.c compilation at -O2 level:
    Overall memory needed: 126408k
    Peak memory use before GGC: 113395k
    Peak memory use after GGC: 83671k
    Maximum of released memory in single GGC run: 32273k
    Garbage: 376144k
    Leak: 10190k
    Overhead: 48541k
    GGC runs: 273

comparing insn-attrtab.c compilation at -O3 level:
    Overall memory needed: 126456k
    Peak memory use before GGC: 113417k
    Peak memory use after GGC: 83695k
    Maximum of released memory in single GGC run: 32593k
    Garbage: 376704k
    Leak: 10208k
    Overhead: 48692k
    GGC runs: 275

comparing Gerald's testcase PR8361 compilation at -O0 level:
    Overall memory needed: 118612k
    Peak memory use before GGC: 95329k
    Peak memory use after GGC: 94374k
    Maximum of released memory in single GGC run: 20170k
    Garbage: 226745k
    Leak: 49361k
    Overhead: 36904k
    GGC runs: 343

comparing Gerald's testcase PR8361 compilation at -O1 level:
  Peak amount of GGC memory allocated before garbage collecting increased from 94382k to 95934k, overall 1.64%
    Overall memory needed: 105688k -> 105988k
    Peak memory use before GGC: 94382k -> 95934k
    Peak memory use after GGC: 93445k
    Maximum of released memory in single GGC run: 19453k -> 20638k
    Garbage: 576028k -> 576046k
    Leak: 55656k -> 55657k
    Overhead: 68545k -> 68544k
    GGC runs: 497 -> 494

comparing Gerald's testcase PR8361 compilation at -O2 level:
  Peak amount of GGC memory allocated before garbage collecting increased from 94382k to 95934k, overall 1.64%
    Overall memory needed: 106204k -> 106936k
    Peak memory use before GGC: 94382k -> 95934k
    Peak memory use after GGC: 93446k
    Maximum of released memory in single GGC run: 19453k -> 20638k
    Garbage: 662699k -> 662684k
    Leak: 56486k -> 56487k
    Overhead: 80314k -> 80312k
    GGC runs: 558 -> 557

comparing Gerald's testcase PR8361 compilation at -O3 level:
  Peak amount of GGC memory allocated before garbage collecting increased from 95467k to 97416k, overall 2.04%
    Overall memory needed: 109696k -> 110232k
    Peak memory use before GGC: 95467k -> 97416k
    Peak memory use after GGC: 94521k
    Maximum of released memory in single GGC run: 19611k -> 21144k
    Garbage: 717203k -> 717126k
    Leak: 57458k
    Overhead: 85177k -> 85177k
    GGC runs: 566 -> 564

Head of the ChangeLog is:

--- /usr/src/SpecTests/sandbox-britten-memory/x86_64/mem-result/ChangeLog	2005-08-29 15:05:49.000000000 +0000
+++ /usr/src/SpecTests/sandbox-britten-memory/gcc/gcc/ChangeLog	2005-08-30 02:44:48.000000000 +0000
@@ -1,3 +1,9 @@
+2005-08-18  Andrew Pinski  <pinskia@physics.uc.edu>
+
+	PR middle-end/23408
+	* ipa-inline.c (cgraph_decide_inlining_incrementally): Remove the
+	call to ggc_collect.
+
 2005-08-18  Paolo Bonzini  <bonzini@gnu.org>
 
 	PR bootstrap/21268


The results can be reproduced by building a compiler with

--enable-gather-detailed-mem-stats targetting x86-64

and compiling preprocessed combine.c or testcase from PR8632 with:

-fmem-report --param=ggc-min-heapsize=1024 --param=ggc-min-expand=1 -Ox -Q

The memory consumption summary appears in the dump after detailed listing
of the places they are allocated in.  Peak memory consumption is actually
computed by looking for maximal value in {GC XXXX -> YYYY} report.

Your testing script.


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