Date: Sun, 5 Dec 2010 22:19:12 -0800 From: Garrett Cooper <gcooper@FreeBSD.org> To: Steve Kargl <sgk@troutmask.apl.washington.edu> Cc: freebsd-current@freebsd.org Subject: Re: Process accounting/timing has broken recently Message-ID: <AANLkTikVDUPFM6Twdz%2B367APxLPS4fswfbqv0m_KLMan@mail.gmail.com> In-Reply-To: <20101206061230.GA69477@troutmask.apl.washington.edu> References: <20101205231829.GA68156@troutmask.apl.washington.edu> <4CFC27A0.8000406@freebsd.org> <20101206061230.GA69477@troutmask.apl.washington.edu>
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On Sun, Dec 5, 2010 at 10:12 PM, Steve Kargl
<sgk@troutmask.apl.washington.edu> wrote:
> 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.
If you can provide the source for the application you're running
above and instructions on how to compile it, I can at least give you a
bit of a head start :).
Thanks,
-Garrett
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