Re: Terminally slow (75 seconds) on some steps

[Andrew Cagney <ac131313@redhat.com>]

> See SYMBOL_SET_NAMES - I fixed that fairly recently.  Also,
> add_psymbol_to_list is how most partial symbols are added; that uses
> the same name cache.  If you're talking about the call to bcache in
> add_psymbol_with_dem_name_to_list, it's only used by hpread.c.  Fixing
> this did in fact improve the hit rate.

Ah.  So the only bcache call is to add the partial symbol to the psymbol 
cache.  That narrows things down a bit.  Wonder if setting 
CHAIN_LENGTH_THRESHOLD lower would help.

>> >c011f6b8 663       2.3393     vmlinux                  do_anonymous_page
>> >00000000 622       2.1946     XFree86                  (no symbols)
>> >08134b74 574       2.0253     gdb                      read_partial_die
> 
>> 
>> Ok, so its spending a lot of time reading partial symbols.
> 
> 
> I've got some plans in this direction... just haven't had time to do
> anything about it yet :(

What about the kernel?  3.5 seconds copying data to the user space is 
suprising.  Can linux, given page sized read requests do it using page 
swapping?

The other question is where in GDB (?) the requests are comming from.  I 
suspect target read, but it could be symbol file related.

Andrew