A recent patch decreased GCC's memory consumption.

gcctest@suse.de gcctest@suse.de
Sat Nov 25 02:20:00 GMT 2006


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 empty function compilation at -O0 level:
    Overall memory needed: 18254k
    Peak memory use before GGC: 2233k
    Peak memory use after GGC: 1940k
    Maximum of released memory in single GGC run: 293k
    Garbage: 422k
    Leak: 2271k
    Overhead: 446k
    GGC runs: 3

comparing empty function compilation at -O0 -g level:
    Overall memory needed: 18270k
    Peak memory use before GGC: 2260k
    Peak memory use after GGC: 1967k
    Maximum of released memory in single GGC run: 293k
    Garbage: 424k
    Leak: 2303k
    Overhead: 450k
    GGC runs: 3

comparing empty function compilation at -O1 level:
    Overall memory needed: 18354k
    Peak memory use before GGC: 2233k
    Peak memory use after GGC: 1940k
    Maximum of released memory in single GGC run: 293k
    Garbage: 427k
    Leak: 2274k
    Overhead: 446k
    GGC runs: 4

comparing empty function compilation at -O2 level:
    Overall memory needed: 18366k
    Peak memory use before GGC: 2233k
    Peak memory use after GGC: 1940k
    Maximum of released memory in single GGC run: 293k
    Garbage: 430k
    Leak: 2274k
    Overhead: 447k
    GGC runs: 4

comparing empty function compilation at -O3 level:
    Overall memory needed: 18366k
    Peak memory use before GGC: 2233k
    Peak memory use after GGC: 1940k
    Maximum of released memory in single GGC run: 293k
    Garbage: 430k
    Leak: 2274k
    Overhead: 447k
    GGC runs: 4

comparing combine.c compilation at -O0 level:
    Overall memory needed: 28442k
    Peak memory use before GGC: 9309k
    Peak memory use after GGC: 8848k
    Maximum of released memory in single GGC run: 2665k
    Garbage: 36852k
    Leak: 6461k
    Overhead: 4869k
    GGC runs: 279

comparing combine.c compilation at -O0 -g level:
    Overall memory needed: 30534k
    Peak memory use before GGC: 10859k
    Peak memory use after GGC: 10489k
    Maximum of released memory in single GGC run: 2415k
    Garbage: 37429k
    Leak: 9271k
    Overhead: 5537k
    GGC runs: 271

comparing combine.c compilation at -O1 level:
    Overall memory needed: 40282k
    Peak memory use before GGC: 17299k
    Peak memory use after GGC: 17124k
    Maximum of released memory in single GGC run: 2274k
    Garbage: 57478k
    Leak: 6515k
    Overhead: 6226k
    GGC runs: 356

comparing combine.c compilation at -O2 level:
    Overall memory needed: 29806k
    Peak memory use before GGC: 17295k
    Peak memory use after GGC: 17124k
    Maximum of released memory in single GGC run: 2866k
    Garbage: 74877k
    Leak: 6621k
    Overhead: 8472k
    GGC runs: 411

comparing combine.c compilation at -O3 level:
    Overall memory needed: 28906k
    Peak memory use before GGC: 18423k
    Peak memory use after GGC: 17851k
    Maximum of released memory in single GGC run: 4100k
    Garbage: 112603k
    Leak: 6688k
    Overhead: 13022k
    GGC runs: 462

    Overall memory needed: 28442k
    Peak memory use before GGC: 9309k
    Peak memory use after GGC: 8848k
    Maximum of released memory in single GGC run: 2665k
    Garbage: 36852k
    Leak: 6461k
    Overhead: 4869k
    GGC runs: 279

comparing combine.c compilation at -O1 level:
    Overall memory needed: 40282k
    Peak memory use before GGC: 17299k
    Peak memory use after GGC: 17124k
    Maximum of released memory in single GGC run: 2274k
    Garbage: 57478k
    Leak: 6515k
    Overhead: 6226k
    GGC runs: 356

comparing combine.c compilation at -O2 level:
    Overall memory needed: 29806k
    Peak memory use before GGC: 17295k
    Peak memory use after GGC: 17124k
    Maximum of released memory in single GGC run: 2866k
    Garbage: 74877k
    Leak: 6621k
    Overhead: 8472k
    GGC runs: 411

comparing combine.c compilation at -O3 level:
    Overall memory needed: 28906k
    Peak memory use before GGC: 18423k
    Peak memory use after GGC: 17851k
    Maximum of released memory in single GGC run: 4100k
    Garbage: 112603k
    Leak: 6688k
    Overhead: 13022k
    GGC runs: 462

comparing insn-attrtab.c compilation at -O0 level:
    Overall memory needed: 88246k
    Peak memory use before GGC: 69793k
    Peak memory use after GGC: 44203k
    Maximum of released memory in single GGC run: 36964k
    Garbage: 129066k
    Leak: 9520k
    Overhead: 17001k
    GGC runs: 216

comparing insn-attrtab.c compilation at -O0 -g level:
    Overall memory needed: 89426k
    Peak memory use before GGC: 70942k
    Peak memory use after GGC: 45459k
    Maximum of released memory in single GGC run: 36964k
    Garbage: 130494k
    Leak: 10951k
    Overhead: 17380k
    GGC runs: 212

comparing insn-attrtab.c compilation at -O1 level:
    Overall memory needed: 114178k
    Peak memory use before GGC: 90379k
    Peak memory use after GGC: 83741k
    Maximum of released memory in single GGC run: 31852k
    Garbage: 277776k
    Leak: 9362k
    Overhead: 29792k
    GGC runs: 221

comparing insn-attrtab.c compilation at -O2 level:
    Overall memory needed: 129386k
    Peak memory use before GGC: 92608k
    Peak memory use after GGC: 84720k
    Maximum of released memory in single GGC run: 30398k
    Garbage: 317198k
    Leak: 9364k
    Overhead: 36371k
    GGC runs: 244

comparing insn-attrtab.c compilation at -O3 level:
  Ovarall memory allocated via mmap and sbrk decreased from 134238k to 129422k, overall -3.72%
    Overall memory needed: 134238k -> 129422k
    Peak memory use before GGC: 92634k
    Peak memory use after GGC: 84746k
    Maximum of released memory in single GGC run: 30585k
    Garbage: 318053k
    Leak: 9367k
    Overhead: 36606k
    GGC runs: 248

comparing Gerald's testcase PR8361 compilation at -O0 level:
    Overall memory needed: 120002k
    Peak memory use before GGC: 93312k
    Peak memory use after GGC: 92385k
    Maximum of released memory in single GGC run: 20013k
    Garbage: 207743k
    Leak: 47730k
    Overhead: 20983k
    GGC runs: 409

comparing Gerald's testcase PR8361 compilation at -O0 -g level:
    Overall memory needed: 132502k
    Peak memory use before GGC: 105441k
    Peak memory use after GGC: 104390k
    Maximum of released memory in single GGC run: 19646k
    Garbage: 214331k
    Leak: 70689k
    Overhead: 26600k
    GGC runs: 380

comparing Gerald's testcase PR8361 compilation at -O1 level:
    Overall memory needed: 119138k
    Peak memory use before GGC: 97923k
    Peak memory use after GGC: 95711k
    Maximum of released memory in single GGC run: 18552k
    Garbage: 446417k
    Leak: 50112k
    Overhead: 32789k
    GGC runs: 559

comparing Gerald's testcase PR8361 compilation at -O2 level:
    Overall memory needed: 119162k
    Peak memory use before GGC: 97924k
    Peak memory use after GGC: 95711k
    Maximum of released memory in single GGC run: 18552k
    Garbage: 505749k
    Leak: 50796k
    Overhead: 40002k
    GGC runs: 613

comparing Gerald's testcase PR8361 compilation at -O3 level:
    Overall memory needed: 118994k
    Peak memory use before GGC: 97968k
    Peak memory use after GGC: 96997k
    Maximum of released memory in single GGC run: 18932k
    Garbage: 526793k
    Leak: 50369k
    Overhead: 40926k
    GGC runs: 627

comparing PR rtl-optimization/28071 testcase compilation at -O0 level:
    Overall memory needed: 137962k
    Peak memory use before GGC: 81913k
    Peak memory use after GGC: 58792k
    Maximum of released memory in single GGC run: 45493k
    Garbage: 147245k
    Leak: 7541k
    Overhead: 25304k
    GGC runs: 82

comparing PR rtl-optimization/28071 testcase compilation at -O0 -g level:
    Overall memory needed: 138138k
    Peak memory use before GGC: 82546k
    Peak memory use after GGC: 59426k
    Maximum of released memory in single GGC run: 45558k
    Garbage: 147415k
    Leak: 9249k
    Overhead: 25769k
    GGC runs: 88

comparing PR rtl-optimization/28071 testcase compilation at -O1 level:
    Overall memory needed: 424334k -> 424266k
    Peak memory use before GGC: 205233k
    Peak memory use after GGC: 201009k
    Maximum of released memory in single GGC run: 101903k
    Garbage: 272136k
    Leak: 47606k
    Overhead: 31282k
    GGC runs: 101

comparing PR rtl-optimization/28071 testcase compilation at -O2 level:
    Overall memory needed: 352386k
    Peak memory use before GGC: 206006k
    Peak memory use after GGC: 201782k
    Maximum of released memory in single GGC run: 108808k
    Garbage: 352361k
    Leak: 48189k
    Overhead: 47027k
    GGC runs: 110

comparing PR rtl-optimization/28071 testcase compilation at -O3 -fno-tree-pre -fno-tree-fre level:
    Overall memory needed: 781310k -> 781378k
    Peak memory use before GGC: 314929k
    Peak memory use after GGC: 293272k
    Maximum of released memory in single GGC run: 165197k
    Garbage: 494379k
    Leak: 65522k
    Overhead: 59885k
    GGC runs: 98

Head of the ChangeLog is:

--- /usr/src/SpecTests/sandbox-britten-memory/x86_64/mem-result/ChangeLog	2006-11-24 08:08:03.000000000 +0000
+++ /usr/src/SpecTests/sandbox-britten-memory/gcc/gcc/ChangeLog	2006-11-25 00:37:31.000000000 +0000
@@ -1,3 +1,40 @@
+2006-11-24  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c/29955
+	* c-tree.h (c_maybe_initialize_eh): New prototype.
+	* c-decl.c (finish_decl): Move EH initialization...
+	(c_maybe_initialize_eh): ... here.  New function.
+	* c-parser.c (c_parser_omp_construct): Call c_maybe_initialize_eh
+	if not #pragma omp atomic.
+
+	PR c/29736
+	* c-common.c (handle_vector_size_attribute): Disallow VECTOR_TYPE
+	or UNION_TYPE inner types.
+
+2006-11-24  Andrew Pinski  <andrew_pinski@playstation.sony.com>
+
+	PR tree-opt/29964
+	* ipa-pure-const.c (check_tree): If the original tree
+	is volatile return early and say the function is not pure
+	nor const.  Remove the volatile check for writes.  
+	(analyze_function): Print out the result of the local
+	analysis pass.
+
+2006-11-24  Joseph Myers  <joseph@codesourcery.com>
+
+	* config/rs6000/eabispe.h (TARGET_DEFAULT): Include
+	MASK_STRICT_ALIGN.
+	* config/rs6000/linuxspe.h (TARGET_DEFAULT): Likewise.
+	* config/rs6000/rs6000.c (rs6000_override_options): Use
+	MASK_STRICT_ALIGN for 8540 and 8548.  Add MASK_STRICT_ALIGN to
+	POWERPC_MASKS.
+
+2006-11-24  Andreas Krebbel  <krebbel1@de.ibm.com>
+
+	* config/s390.c (s390_emit_compare_and_swap): New function.
+	(s390_expand_cs_hqi, s390_expand_atomic): Call 
+	s390_emit_compare_and_swap.
+
 2006-11-23  John David Anglin  <dave.anglin@nrc-cnrc.gc.ca>
 
 	* pa.c (return_addr_rtx): Change 0xe0400002 to -532676606.


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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