From: Daniel Jacobowitz <drow@mvista.com>
To: Andrew Cagney <ac131313@redhat.com>
Cc: Elena Zannoni <ezannoni@redhat.com>,
David Carlton <carlton@math.stanford.edu>,
gdb <gdb@sources.redhat.com>, Jim Blandy <jimb@redhat.com>
Subject: Re: DW_AT_specification and partial symtabs
Date: Fri, 13 Jun 2003 16:34:00 -0000 [thread overview]
Message-ID: <20030613163444.GA14030@nevyn.them.org> (raw)
In-Reply-To: <3EE9FA99.8070201@redhat.com>
On Fri, Jun 13, 2003 at 12:23:53PM -0400, Andrew Cagney wrote:
> >On Fri, Jun 13, 2003 at 11:38:38AM -0400, Andrew Cagney wrote:
> >
> >>Daniel wrote:
> >>
> >>
> >
> >>> > 1) is very easy to measure. GDB has a command line option --readnow
> >>> > which forces symtabs to be read in immediately. I tried my normal
> >>> > performance testcase: a dummy main() linked to all of mozilla's
> >>> > component libraries, with full stabs debug info. Note stabs, not
> >>> > DWARF2, so the timing may vary. Also note that we duplicate psymtab
> >>> > and symtab creation doing it this way, so it overestimates the cost.
> >
> >>
> >>I think that's an understatement.
> >
> >
> >Not really. You can subtract the psymtab time from the combined time,
> >and then compare. It still more than triples the time.
>
> So we agree, 25% is significant but 3% is not.
>
> A better question is what % of symtabs get draged in by a C++ `break
> main; run'. Wasn't the original conjecture that symtabs get sucked in
> anyway so why do it twice.
I am pretty sure that the conjecture is false. I've fixed several
things in this area.
I run GDB on target boards, over NFS root, with limited RAM, and full
debug info for libc and libstdc++. When I mess up lazy loading, I
_notice_. At least I'm not working on the 3MHz FPGA right now.
--
Daniel Jacobowitz
MontaVista Software Debian GNU/Linux Developer
next prev parent reply other threads:[~2003-06-13 16:34 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-06-12 17:01 David Carlton
2003-06-12 17:05 ` Daniel Jacobowitz
2003-06-12 17:10 ` David Carlton
2003-06-12 17:20 ` Elena Zannoni
2003-06-12 22:17 ` David Carlton
2003-06-13 13:36 ` Daniel Jacobowitz
2003-06-13 14:00 ` Elena Zannoni
2003-06-13 15:38 ` Andrew Cagney
2003-06-13 15:50 ` Daniel Jacobowitz
2003-06-13 15:57 ` Andrew Cagney
2003-06-13 16:24 ` Andrew Cagney
2003-06-13 16:34 ` Daniel Jacobowitz [this message]
2003-06-17 0:09 ` David Carlton
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