[Bug symtab/14002] New: big cpu/mem hog on large c++ applications.

[Bug symtab/14002] New: big cpu/mem hog on large c++ applications.

[pluto at agmk dot net]

http://sourceware.org/bugzilla/show_bug.cgi?id=14002

             Bug #: 14002
           Summary: big cpu/mem hog on large c++ applications.
           Product: gdb
           Version: 7.4
            Status: NEW
          Severity: critical
          Priority: P2
         Component: symtab
        AssignedTo: unassigned@sourceware.org
        ReportedBy: pluto@agmk.net
    Classification: Unclassified


hi,

i have a large c++ application (2.9GB of shared objects, 600MB of static
archives used in shared objects). on isolated part of sources a single
'next' call takes ~3 minutes and increases memory usage from ~500M to ~3G
while previous gdb-7.3.1 needs only 2..3 seconds and increases memory usage
from ~400M to ~550MB.

7bd518fd9738c50a5197af2b184acd97e4d4df40 is the first bad commit

commit 7bd518fd9738c50a5197af2b184acd97e4d4df40
Author: Tom Tromey <tromey@redhat.com>
Date:   Mon Jul 11 17:17:25 2011 +0000

        * dwarf2read.c (handle_DW_AT_stmt_list): New function.
        (read_file_scope, read_type_unit_scope): Use it.


link to gdb mailinglist discussion:
http://sourceware.org/ml/gdb/2012-03/msg00096.html

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[Bug symtab/14002] big cpu/mem hog on large c++ applications.

[pluto at agmk dot net]

http://sourceware.org/bugzilla/show_bug.cgi?id=14002

Pawel Sikora <pluto at agmk dot net> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |x86_64-gnu-linux
                 CC|                            |jan.kratochvil at redhat
                   |                            |dot com, tromey at redhat
                   |                            |dot com
               Host|                            |x86_64-gnu-linux
              Build|                            |x86_64-gnu-linux

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[Bug symtab/14002] big cpu/mem hog on large c++ applications.

[pluto at agmk dot net]

http://sourceware.org/bugzilla/show_bug.cgi?id=14002

--- Comment #1 from Pawel Sikora <pluto at agmk dot net> 2012-04-24 19:59:47 UTC ---
current git/master (2e523a5f18498a902d55ae293cb3870d060f6a6b) is also affected.

here's quick info about project:

/* buildenv: boost + other libs */
$ find buildenv -type f -name '*.h' -o -name '*.c' -o -name '*.?pp' |wc -l
9728

/* core project sources */
$ find sources -type f -name '*.h' -o -name '*.c' -o -name '*.?pp' |wc -l
7488

so, there's ~17k sources which may be recorded in dwarf-4 (-g2) debuginfo.
for the tested slow-step-place, callgrind shows ~921k start_subfile() calls
and ~520M filename_cmp() calls (from start_subfile). so, i think that linear
scanning of subfile list and multiple deduce_language_from_filename
have non-trivial performance impact.

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[Bug symtab/14002] big cpu/mem hog on large c++ applications.

[pluto at agmk dot net]

http://sourceware.org/bugzilla/show_bug.cgi?id=14002

--- Comment #2 from Pawel Sikora <pluto at agmk dot net> 2012-04-28 16:51:28 UTC ---
i've rebuilt the whole project with -fno-debug-type-sections (gcc-4.7)
and 7.4/master works as fast as 7.3.1 now. so, it looks like a serious
performance problem with .debug_types handling.

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[Bug symtab/14002] big cpu/mem hog on large c++ applications.

[dje at google dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14002

dje at google dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dje at google dot com
         AssignedTo|unassigned at sourceware    |dje at google dot com
                   |dot org                     |

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[Bug symtab/14002] big cpu/mem hog on large c++ applications.

[loic.yhuel at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14002

Loïc Yhuel <loic.yhuel at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |loic.yhuel at gmail dot com

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[Bug symtab/14002] big cpu/mem hog on large c++ applications.

[dje at google dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=14002

dje at google dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|                            |FIXED

--- Comment #3 from dje at google dot com 2012-11-13 22:40:50 UTC ---
This should be fixed now.
Please reopen if not.

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