Open file dialog extremely slow on network drive

[mmueller]

User reported that cgdb will thrash for 20+ minutes at 100% CPU after hitting 'o' to open a file where the sources are hosted on an NFS drive. Running info sources in gdb completes in a few seconds, so this is likely a bug in cgdb.

See discussion here: https://groups.google.com/forum/?fromgroups=#!topic/cgdb-users/BtI9ze4g9Ts

[michaeljones]

Thank you for following this up. In case it is of use I'm working with a version compiled from source from:

7e06def1980cda4eb79b957d98cc44a2b7f53264

Which is a few changes ahead of v0.6.7 but changes are in readme and non-code files.

Michael

[michaeljones]

Without indentation (so it auto-links): 7e06def

[michaeljones]

Hi,

I'm not sure if this sheds any light on it but I attached gdb to cgdb and interrupted during this hang. The stacktrace is so short I guess it either tells you everything or nothing:

Program received signal SIGINT, Interrupt.
0x00007f19134bd003 in __select_nocancel () at ../sysdeps/unix/syscall-template.S:82
82  in ../sysdeps/unix/syscall-template.S
(gdb) where
#0  0x00007f19134bd003 in __select_nocancel () at ../sysdeps/unix/syscall-template.S:82
#1  0x0000000000403bc3 in main_loop () at cgdb.c:1338
#2  main (argc=<optimized out>, argv=<optimized out>) at cgdb.c:1735
(gdb) 

Hope it is of some use. I'm happy to perform more tests if you feel there is anything else I can do.

Cheers,
Michael

[michaeljones]

Hi,

To clarify, if I do a "next" step in gdb it hangs again. So it doesn't seem to be doing a loop and coming back to that, it is hanging on the __select_nocancel. If I knew more about system calls and the like I might have some idea what that meant :)

Cheers,
Michael

[mmueller]

Thanks, that actually debunks a theory I had. Unfortunately, I don't have a new theory yet. I'll try to investigate some more.

[BarrettLowe]

Has anyone run into this again lately? My thought was to cache the file list each time the sources are reloaded. My configuration doesn't hang as long but each time I try to open the file dialog over NFS, it's a delay of a couple of seconds. Slows down the workflow just enough to be frustrating.

[brasko]

On Fri, Aug 12, 2016 at 06:45:59AM -0700, BarrettLowe wrote:

Has anyone run into this again lately? My thought was to cache the file list each time the sources are reloaded. My configuration doesn't hang as long but each time I try to open the file dialog over NFS, it's a delay of a couple of seconds. Slows down the workflow just enough to be frustrating.

Hi,

Please run, gdb --annotate=2 ./debugged program,

Then run the command, "maint set per-command time on".

Then time how long the command, 'info sources' takes.
Also let me know how long gdb thought it took. Should look
something like,
Command execution time: 0.000000 (cpu), 0.000105 (wall)
but much longer for you.

If GDB is the one taking a long time, there is nothing we can do
and we'll close the issue. If GDB is quick and CGDB is slow, we
can fix it.

Thanks,
Bob Rossi

[mikesart]

Closing really old bugs (and cgdb switched to gdb/mi). If this still is a problem, please open a new bug. Thanks much.