-fomit-frame-pointer
Don't keep the frame pointer in a register for functions that don't
need one. This avoids the instructions to save, set up and restore
frame pointers; it also makes an extra register available in many
functions. It also makes debugging impossible on some machines.
On some machines, such as the VAX, this flag has no effect, because the
standard calling sequence automatically handles the frame pointer and
nothing is saved by pretending it doesn't exist. The
machine-description macro FRAME_POINTER_REQUIRED controls whether a
target machine supports this flag. See Register Usage.
Enabled at levels -O, -O2, -O3, -Os.
As being told in the gcc man :)
Eelco
On 28-okt-03, at 10:20, Shih Ming-Wei wrote:
I don't think -O -O1 and -O2 impliciet -fomit-fram-pointer
not sure about -O3
Ming-Wei
> -----Original Message-----
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED] Behalf
> Of Eelco van Beek - IC&S
> Sent: Tuesday, October 28, 2003 9:37 AM
> To: [email protected]
> Subject: Re: [Dbmail] 100% cpu usage with dbmail-pop3d --
> SOLVED, for me
> at least
>
>
> I thought the stable version was compiled with -O which automatically
> enables the omission of frame pointer usage?
>
> Best regards,
>
> Eelco
>
> On 27-okt-03, at 23:08, Bret Baptist wrote:
>
> > On Friday 24 October 2003 5:35 am, Shih Ming-Wei wrote:
> >> hi,
> >>
> >> I have solve the 99% CPU usage on Linux/sparc systems that
> >> we are using, apparently changing CFLAGS from "-O2 -pipe" to
> >> "-march=v8 -mtune=v9 -O2 -pipe -fomit-frame-pointer" cahnges
> >> the CPU usage from 99% to max 1.8% (avg 0.4 %). So my
> >> conclusion is this is not a dbmail bug but dbmail must trigger
> >> some bug in platform/compiler/glibc,
> >>
> >> Just my 2 cents
> >>
> >>
> >> Hope this might help someone else
> >>
> >> Ming-Wei
> >
> > After more testing I have found that the important bit here is the
> > -fomit-frame-pointer. If I define that I don't get the
> excessive CPU
> > usage.
> > Is there any reason for not making this a standard compile flag?
> >
> > I am running debian testing (sarge):
> >
> > Which has:
> >
> > gcc-3.3.1-2
> > kernel: 2.4.18-bf2.4 #1 Son Apr 14 09:53:28 CEST 2002 i686
GNU/Linux
> > libc6-2.3.2-7
> > mysql-client-4.0.13-3
> >
> > Anything else relevant?
> >
> > --
> > Bret Baptist
> > Systems and Technical Support Specialist
> > [EMAIL PROTECTED]
> > Internet Exposure, Inc.
> >http://www.iexposure.com
> >
> > (612)676-1946 x17
> > Web Development-Web Marketing-ISP Services
> > ------------------------------------------
> >
> >
> > Today is the tomorrow you worried about yesterday.
> >
> > _______________________________________________
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> >
> _________________________
> E.J.A. van Beek
> ICT Manager
> IC&S
> T: +31 30 2322878
> F: +31 30 2322305
>
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> www.ic-s.nl/keys/eelco.txt
>
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>
_________________________
E.J.A. van Beek
ICT Manager
IC&S
T: +31 30 2322878
F: +31 30 2322305
PGP-key:
www.ic-s.nl/keys/eelco.txt
