Date: Sun, 5 Dec 2010 22:12:30 -0800 From: Steve Kargl <sgk@troutmask.apl.washington.edu> To: Julian Elischer <julian@freebsd.org> Cc: freebsd-current@freebsd.org Subject: Re: Process accounting/timing has broken recently Message-ID: <20101206061230.GA69477@troutmask.apl.washington.edu> In-Reply-To: <4CFC27A0.8000406@freebsd.org> References: <20101205231829.GA68156@troutmask.apl.washington.edu> <4CFC27A0.8000406@freebsd.org>
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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
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