Date: Tue, 11 Nov 1997 12:16:38 -0800 (PST)
Message-Id: <199711112016.MAA18277@adit.ap.net>
Mime-Version: 1.0
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To: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>
From: Nate Eldredge <eldredge AT ap DOT net>
Subject: Re: Curious: How does DJGPP profile __dpmi_int?
Cc: djgpp AT delorie DOT com
Precedence: bulk

At 10:21  11/10/1997 +0200, Eli Zaretskii wrote:
>
>On Sun, 9 Nov 1997, Nate Eldredge wrote:
>
>> That's my question. How is it possible for __dpmi_int to show up on
>> profiling outputs of DJGPP programs? I looked at its sources, expecting to
>> find a call to _mcount (the function that's called on entry to a profiled
>> function and sets up its profiling), but I didn't.
>
>I think it's for the same reason other library functions appear in
>the profile, although the library wasn't compiled with -pg.
>
>The reason is that the profile is also gathered on timer tick
>interrupts.  The interrupt handler records the EIP and later
>gprof translates it into a symbol by looking at the debug info
>in the executable (much like the debugger does).
Oh, okay. It just tends to show up more often since it usually takes longer.
I get it. Thanks.
>
>> It's a nice feature, but how the heck is it done? I think it's magic.
>
>"Any sufficiently high technology is indistinguishable from magic."  
>(A. Einstein)
Right. :)

Nate Eldredge
eldredge AT ap DOT net