Subject: fftw_test failing on Core 2 Duo/GENERIC.MP
To: None <firstname.lastname@example.org>
From: Brad du Plessis <email@example.com>
Date: 11/30/2007 09:22:39
On this system a few of days ago (Intel DG33FB, Intel 2180, 4.0_RC3
GENERIC.MP) I encountered random segmentation faults when trying to
build pkgsrc packages. The build would run for a while and would then
die with a seg fault. I had a suspicion that the RAM may be faulty so I
ran memtest-86 and it ran flawlessly for 2 hours.
I then built the benchmarking utility benchfft in
pkgsrc/benchmarks/benchfft and I ran the app fftw_test on this system.
After running fftw_test -r (2 of them, one for each core) for a couple
of hours it reported a calculation failure. The second instance of
fftw_test failed about an hour later.
I then tried fftw_test on all the hardware I could get my hands on (see
the results below). I regard a system that can run this test for more
than 24 hours as a pass. The systems where I've added "(1 core)" are
dual core systems that have had the second core disabled in the BIOS.
I've run memtest on the systems with the E2180 and the E2140 CPUs and no
errors were found. The systems that passed were tested with 2 instances
of fftw_test running at the same time, and were then retested with only
one instance of fftw_test running.
Motherboard ; CPU ; Kernel ; Result
Intel DG33FB ; Intel E2180 ; 4.0_RC3 GENERIC.MP ; FAILED
Intel DG33FB ; (1 core) Intel E2180 ; 4.0_RC3 GENERIC.MP ; PASSED
Intel DG33FB ; Intel E2160 ; 4.0_RC4 GENERIC.MP ; FAILED
Intel DG33FB ; (1 core) Intel E2160 ; 4.0_RC4 GENERIC.MP ; PASSED
Intel DG33FB ; Intel E2140 ; 4.0_RC3 GENERIC.MP ; FAILED
Intel DG33FB ; (1 core) Intel E2140 ; 4.0_RC3 GENERIC.MP ; PASSED
Asus P5PE-VM ; Intel E6600 ; 3.1_RC2 GENERIC.MP ; FAILED
Asus P5PE-VM ; Intel E6600 ; 3.1_RC2 GENERIC ; PASSED
DFI G7V-600B ; Intel P4-3.0GHz ; 3.1_STABLE GENERIC ; PASSED
Intel DG31PR ; Intel Cel. 420 ; 4.0_RC3 GENERIC.MP ; PASSED
You'll note that what is a bit concerning is that no system running with
both cores enabled passed this test. Has anyone else by any chance tried
this on a Core 2 Duo system and seen similar results?
Is this something to worry about, or is this a bogus test?