* 5.1 extremely slow
@ 2002-03-10 10:48 John Firebaugh
2002-03-10 11:04 ` John Firebaugh
0 siblings, 1 reply; 3+ messages in thread
From: John Firebaugh @ 2002-03-10 10:48 UTC (permalink / raw)
To: gdb
[-- Attachment #1: Type: text/plain, Size: 1004 bytes --]
Hi,
I've upgraded to 5.1.1 due to bugs in 4.x, but debugging almost any program is
unbearably slow. I've attached some detailed debug output; here is a summary:
In the file gdb_commands I put:
break main
r
k
q
Compare running the command "time strace -c gdb -x gdb_commands
src/.libs/gideon" under 4.18 and 5.1.1:
4.18:
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
44.44 0.153028 23 6763 ptrace
real 0m4.299s
user 0m2.550s
sys 0m0.810s
5.1.1:
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
98.07 26.668416 27 986910 ptrace
real 1m9.949s
user 0m20.750s
sys 0m40.540s
Note the nearly 1 million calls to ptrace with 5.1: more than a hundred-fold
increase compared to 4.18.
If you need more detailed strace output or any other info, let me know.
Thanks,
John
[-- Attachment #2: gdb_test --]
[-- Type: text/plain, Size: 6210 bytes --]
The contents of gdb_commands:
break main
r
k
q
With gdb 4.18:
john@localhost:~/src/kde/gideon$ time strace -c gdb -x gdb_commands src/.libs/gideon
execve("/usr/bin/gdb", ["gdb", "-x", "gdb_commands", "src/.libs/gideon"], [/* 30 vars */]) = 0
GNU gdb 4.18
Copyright 1998 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "powerpc-unknown-linux-gnu"...(no debugging symbols found)...
Breakpoint 1 at 0x1000b034
(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...
(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...
(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...
(no debugging symbols found)...(no debugging symbols found)...
Breakpoint 1, 0x1000b034 in main ()
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
44.44 0.153028 23 6763 ptrace
43.86 0.151007 214 705 read
4.84 0.016659 9 1911 brk
2.67 0.009180 656 14 write
0.96 0.003321 33 102 15 open
0.87 0.002998 35 85 munmap
0.63 0.002167 4 497 _llseek
0.48 0.001649 13 129 mmap
0.22 0.000752 4 173 fcntl64
0.17 0.000599 599 1 fork
0.17 0.000586 8 77 close
0.17 0.000580 13 43 ioctl
0.14 0.000482 4 122 rt_sigaction
0.14 0.000466 5 87 fstat64
0.11 0.000363 9 41 fstat
0.03 0.000098 25 4 1 stat
0.03 0.000091 4 26 getrusage
0.03 0.000091 9 10 wait4
0.01 0.000041 5 9 kill
0.01 0.000037 12 3 mprotect
0.01 0.000031 10 3 stat64
0.01 0.000030 15 2 getcwd
0.01 0.000019 19 1 uname
0.00 0.000014 4 4 setfsuid
0.00 0.000012 3 4 setfsgid
0.00 0.000008 4 2 getuid
0.00 0.000006 3 2 geteuid
0.00 0.000005 3 2 getgid
0.00 0.000005 3 2 getegid
------ ----------- ----------- --------- --------- ----------------
100.00 0.344325 10824 16 total
real 0m4.299s
user 0m2.550s
sys 0m0.810s
With gdb 5.1.1:
john@localhost:~/src/kde/gideon$ time strace -c gdb -x gdb_commands src/.libs/gideon
execve("/usr/bin/gdb", ["gdb", "-x", "gdb_commands", "src/.libs/gideon"], [/* 30 vars */]) = 0
GNU gdb 5.1.1
Copyright 2002 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "powerpc-linux"...(no debugging symbols found)...
Breakpoint 1 at 0x1000b034
(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...
(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...
(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...(no debugging symbols found)...
(no debugging symbols found)...(no debugging symbols found)...[New Thread 1024 (LWP 22645)]
[Switching to Thread 1024 (LWP 22645)]
Breakpoint 1, 0x1000b034 in main ()
% time seconds usecs/call calls errors syscall
------ ----------- ----------- --------- --------- ----------------
98.07 26.668416 27 986910 ptrace
1.67 0.453464 634 715 read
0.12 0.032433 21 1542 brk
0.03 0.009060 18 504 _llseek
0.03 0.007432 85 87 munmap
0.02 0.005656 354 16 write
0.02 0.004501 40 112 22 open
0.01 0.003132 17 183 rt_sigprocmask
0.01 0.001937 14 137 mmap
0.00 0.001284 51 25 11 wait4
0.00 0.000798 5 175 fcntl64
0.00 0.000737 737 1 fork
0.00 0.000699 16 44 ioctl
0.00 0.000571 7 80 close
0.00 0.000501 4 123 rt_sigaction
0.00 0.000481 5 90 fstat64
0.00 0.000302 8 40 fstat
0.00 0.000096 4 26 getrusage
0.00 0.000069 23 3 1 stat
0.00 0.000066 13 5 mprotect
0.00 0.000061 31 2 getcwd
0.00 0.000052 13 4 rt_sigsuspend
0.00 0.000050 25 2 1 access
0.00 0.000030 10 3 stat64
0.00 0.000019 19 1 uname
0.00 0.000019 19 1 poll
0.00 0.000016 5 3 kill
------ ----------- ----------- --------- --------- ----------------
100.00 27.191882 990834 35 total
real 1m9.949s
user 0m20.750s
sys 0m40.540s
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: 5.1 extremely slow
2002-03-10 10:48 5.1 extremely slow John Firebaugh
@ 2002-03-10 11:04 ` John Firebaugh
2002-03-10 11:23 ` Daniel Jacobowitz
0 siblings, 1 reply; 3+ messages in thread
From: John Firebaugh @ 2002-03-10 11:04 UTC (permalink / raw)
To: gdb
On Sunday 10 March 2002 10:47, John Firebaugh wrote:
> I've upgraded to 5.1.1 due to bugs in 4.x, but debugging almost any program
> is unbearably slow. I've attached some detailed debug output; here is a
> summary:
Update: this is probably the same problem discussed in the thread "gdb and
dlopen":
http://sources.redhat.com/ml/gdb/2001-10/msg00157.html
Is there a fix for this yet?
-John
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: 5.1 extremely slow
2002-03-10 11:04 ` John Firebaugh
@ 2002-03-10 11:23 ` Daniel Jacobowitz
0 siblings, 0 replies; 3+ messages in thread
From: Daniel Jacobowitz @ 2002-03-10 11:23 UTC (permalink / raw)
To: John Firebaugh; +Cc: gdb
On Sun, Mar 10, 2002 at 11:03:39AM -0800, John Firebaugh wrote:
> On Sunday 10 March 2002 10:47, John Firebaugh wrote:
> > I've upgraded to 5.1.1 due to bugs in 4.x, but debugging almost any program
> > is unbearably slow. I've attached some detailed debug output; here is a
> > summary:
>
> Update: this is probably the same problem discussed in the thread "gdb and
> dlopen":
>
> http://sources.redhat.com/ml/gdb/2001-10/msg00157.html
>
> Is there a fix for this yet?
Not yet. It's a tricky problem, because we lose the ability to set
breakpoints in early functions in shared libraries if we fix it.
You aren't seeing that problem specifically as much as the hideous
performance of the threads package. There's no way to disable thread
debugging (should we add a set for that? I think we should!) but you
can temporarily remove or make unreadable /lib/libthread_db.so.1 to
disable it. It will automatically kick in if you are linked to
-lpthread.
We need to address some of the performance concerns of this code very
badly. I have a few ideas but they will not be in time for 5.2.
--
Daniel Jacobowitz Carnegie Mellon University
MontaVista Software Debian GNU/Linux Developer
^ permalink raw reply [flat|nested] 3+ messages in thread
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2002-03-10 11:04 ` John Firebaugh
2002-03-10 11:23 ` Daniel Jacobowitz
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