Subject: Re: callgraph ARM7
To: None <Richard.Earnshaw@arm.com>
From: Ben Harris <email@example.com>
Date: 09/25/2001 13:34:21
On Tue, 25 Sep 2001, Richard Earnshaw wrote:
> Secondly, you need to find out where all those calls to SetCPSR are coming
> from. SetCPSR is currently defined as ENTRY_NP, though I'm not entirely
> sure that this is required.
It is required, because it's used by mcount to protect its internal data
structures. See the end of <machine/profile.h>.
Note that apparently spending a lot of time in SetCPSR may not be
significant. Anything which blocks all interrupts will get any statclock
interrupt queued up and delivered when interrupts are re-enabled, which is
always in SetCPSR. You can probably make this better by having real
statclock interrupts like arm26 does, and perhaps by arranging that
SetCPSR restore the I flag at the same time as it returns (like
int_restore does on arm26).
> Try building a kernel where it is just a normal ENTRY function.
This should crash as soon as a profiled function is called.
Ben Harris <firstname.lastname@example.org>
Portmaster, NetBSD/arm26 <URL:http://www.netbsd.org/Ports/arm26/>