[Bug symtab/15412] New: Performance regression in "info {func,var,types} foo" (mostly info types).

[Bug symtab/15412] New: Performance regression in "info {func,var,types} foo" (mostly info types).

[dje at google dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15412

             Bug #: 15412
           Summary: Performance regression in "info {func,var,types} foo"
                    (mostly info types).
           Product: gdb
           Version: unknown
            Status: NEW
          Severity: normal
          Priority: P2
         Component: symtab
        AssignedTo: unassigned@sourceware.org
        ReportedBy: dje@google.com
    Classification: Unclassified


In a large program I'm seeing a performance regression in
info {func,var,types} ^foo::(anonymous namespace)

For example, in 7.5 it takes 2 seconds, in 7.6 and cvs head it takes ~300
seconds.

I think there are multiple factors here because a comparison of gdb
before/after the type-pretty-printing patches of ~2012-11-12 I only see a perf
degradation from 2 seconds to 150 seconds.  So something after that is then
slowing things down from 150s to 300s.

Data point: If I hack "info {func,var,type}" to set type_print_options.raw = 1,
I get most (maybe all) the performance back.

It seems like we want type-pretty-printing for info types, but the performance
cost can be high.  Thus I'm thinking "info {func,var,types}" should have a /r
(raw) option.

OTOH, a lot of the cost can be reduced, I think, by caching lookups: the same
symbol is processed many(!!!) times.  The caching could be at multiple levels
(e.g., more than just simple symbol lookups), I'm not sure what's the best one
yet.

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[Bug symtab/15412] Performance regression in "info {func,var,types} foo" (mostly info types).

[tobias.hunger at digia dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15412

Tobias Hunger <tobias.hunger at digia dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |tobias.hunger at digia dot
                   |                            |com

--- Comment #1 from Tobias Hunger <tobias.hunger at digia dot com> 2013-05-17 10:09:22 UTC ---
I see the same issue debugging C++ applications using GDB 7.6 with Qt Creator. 

Getting a list of local variables and their values after hitting a breakpoint
takes at least 10s where it is almost instantaneous in GDB 7.5.

This time can increase dramatically (> 2 min!) with the complexity of the code
containing the breakpoint.

GDB 7.6 is not usable in this setup, I had to revert back to GDB 7.5. I would
seriously consider raising the importance of this regression.

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[Bug symtab/15412] Performance regression in "info {func,var,types} foo" (mostly info types).

[xunxun1982 at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15412

xunxun <xunxun1982 at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |xunxun1982 at gmail dot com

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[Bug symtab/15412] Performance regression in "info {func,var,types} foo" (mostly info types).

[asmwarrior at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15412

asmwarrior <asmwarrior at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |asmwarrior at gmail dot com

--- Comment #2 from asmwarrior <asmwarrior at gmail dot com> 2013-05-24 13:49:03 UTC ---
I see the same regression here under MinGW GDB CVS 2013-05-24, when I try to
run the command "ptype wxEvent", then GDB goes to hang/loop for a long time(I
just kill it), but for a GDB cvs build 2012-08-17, the response is less than a
second.

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[Bug symtab/15412] Performance regression in "info {func,var,types} foo" (mostly info types).

[asmwarrior at gmail dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15412

--- Comment #3 from asmwarrior <asmwarrior at gmail dot com> 2013-05-24 14:33:41 UTC ---
As DJE said, the workaround looks like below:
 gdb/typeprint.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gdb/typeprint.c b/gdb/typeprint.c
index 4e70593..6e62922 100644
--- a/gdb/typeprint.c
+++ b/gdb/typeprint.c
@@ -62,7 +62,7 @@ const struct type_print_options type_print_raw_options =

 static struct type_print_options default_ptype_flags =
 {
-  0,                /* raw */
+  1,                /* raw */
   1,                /* print_methods */
   1,                /* print_typedefs */
   NULL,                /* local_typedefs */

Adding a command like below should be better I think:
"show print type raw"
"set print type raw"

We have already "set print type method" and "set print type typedef"

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[Bug symtab/15412] Performance regression in "info {func,var,types} foo" (mostly info types).

[andre.poenitz at digia dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15412

Andre Poenitz <andre.poenitz at digia dot com> changed:

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                 CC|                            |andre.poenitz at digia dot com

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[Bug symtab/15412] Performance regression in "info {func,var,types} foo" (mostly info types).

[flq at live dot com]

http://sourceware.org/bugzilla/show_bug.cgi?id=15412

Linqing Feng <flq at live dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |flq at live dot com

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[Bug symtab/15412] Performance regression in "info {func,var,types} foo" (mostly info types).

[altsysrq at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=15412

Vladimir Rutsky <altsysrq at gmail dot com> changed:

           What    |Removed                     |Added
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                 CC|                            |altsysrq at gmail dot com

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[Bug symtab/15412] Performance regression in "info {func,var,types} foo" (mostly info types).

[asmwarrior at gmail dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=15412

--- Comment #4 from asmwarrior <asmwarrior at gmail dot com> ---
Some test result: GDB GIT HEAD 7.7.50.20140611-cvs(with python enabled, but
without the hack patch of comment 3). When debugging a large Codeblocks project
with debug wxWidgets library. "ptype wxEvent" returned instantly, and "info
types wxEvent" takes about 60 seconds. But compared with my comment 2, it looks
like the performance has improved.

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[Bug symtab/15412] Performance regression in "info {func,var,types} foo" (mostly info types).

[dje at google dot com]

https://sourceware.org/bugzilla/show_bug.cgi?id=15412

dje at google dot com changed:

           What    |Removed                     |Added
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           Keywords|                            |performance

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