Re: Process accounting/timing has broken recently

On Sun, Dec 05, 2010 at 04:00:32PM -0800, Julian Elischer wrote:
> On 12/5/10 3:18 PM, Steve Kargl wrote:
> >Sometime in the last 7-10 days, some one made a
> >change that has broken process accounting/timing.
> >
> >laptop:kargl[42] foreach i ( 0 1 2 3 4 5 6 7 8 9 )
> >foreach? time ./testf
> >foreach? end
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        69.55 real        38.39 user        30.94 sys
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        68.82 real        40.95 user        27.60 sys
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        69.14 real        38.90 user        30.02 sys
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        68.79 real        40.59 user        27.99 sys
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        68.93 real        39.76 user        28.96 sys
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        68.71 real        41.21 user        27.29 sys
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        69.05 real        39.68 user        29.15 sys
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        68.99 real        39.98 user        28.80 sys
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        69.02 real        39.64 user        29.16 sys
> >Max ULP: 0.501607 for x in [-18.000000:88.709999] with dx = 1.067100e-04
> >        69.38 real        37.49 user        31.67 sys
> >
> >testf is a numerically intensive program that tests the
> >accuracy of expf() in a tight loop.  User time varies
> >by ~3 seconds on my lightly loaded 2 GHz core2 duo processor.
> >I'm fairly certain that the code does not suddenly grow/loose
> >6 GFLOP of operations.
> >
> I know it's a lot to ask but it may be something that you can help 
> with if you
> had the time to triangulate in on the change that did it..
> I presume that since you are an "old hand" you can check out sources 
> at different revisions..

I was hoping that someone (possibly the person responsible) would
recognize the symptoms and recommend a revision or two to revert.
Otherwise, doing a binary search will take some time in that it
takes 4+ hours for a buildworld/kernel cycle on my laptop.

-- 
Steve