strange top statistics for 3.1 cc1

[Brad Lucier]

> 
> Brad Lucier wrote:
> > 
> > > Could you give a source file and a cc1 command line to help track
> > > this down?
> > 
> > [lucier@curie lib]$ gcc -fpic -fomit-frame-pointer -O1 -fno-math-errno -fschedule-insns2 -fno-strict-aliasing -Wall -W -Wno-unused  -c -I.  -D___PRIMAL -D___LIBRARY -D___SHARED -D___SINGLE_HOST _num.c -save-temps
> > 
> > and
> > 
> > http://www.math.purdue.edu/~lucier/_num.i.gz
> 
> Thanks.
> 
> Some remarks.  I am using the trunk checked out today, configured
> identically to yours
> (except for --prefix). I am also running Red Hat 7.1, with the updated
> 2.4.3-12 kernel,
> on a 533 MHz Celeron box.
> 
> This case is weird.  When I first started running the testcase, it
> looked as though I
> wasn't seeing your problem.  I let it run for some 14 CPU minutes and
> never saw any
> sign of excessive system CPU usage.
> 
> Then I tried running it again under /usr/bin/time, so that I could get a
> total cpu usage
> report, and went to do other things.
> 
> Well, it's still running, having consumed more than 160 CPU minutes! 
> And now I see the
> system CPU usage effect you describe.  I tried attaching to the process
> under GDB, and
> I saw it was bogged down in split_all_insns() at line 3486 of toplev.c,
> doing lots of
> sbitmap operations.  Doing strace -p on the process showed that it was
> performing lots of
> mmap2() and munmap() calls, each mapping and unmapping a large sbitmap
> (about 11 MB).
> 
> I think this is where some of your excessive system CPU usage is coming
> from.
> 
> Just how long did it take you to compile this testcase, anyway?

I don't know, I went to bed and it was done in the morning.

> 
> (This reply probably won't show up on the list.  It looks like the Pac
> Bell SMTP server
> I use has been ORBL'd due to some <bleep> who attached an open relay to
> it.)
> 

So I kept the whole message in my reply.

Brad