Re: [Numpy-discussion] Buildbot failures since r5443

On Thu, Jul 17, 2008 at 10:51 AM, Robert Kern wrote:

On Thu, Jul 17, 2008 at 03:19, Pauli Virtanen wrote:

...

Hi,

Since r5443 the Sparc buildbots show a "Bus error" in the test phase:

http://buildbot.scipy.org/builders/Linux_SPARC_64_Debian/ builds/102/steps/shell_2/logs/stdio

while the one on FreeBSD-64 passes.

In the test that's failing (test_filled_w_flexible_dtype), a structured array with a dtype of [('i',int), ('s','|S3'), ('f',float)] is created. I'm guessing that the final C double in that record is not getting aligned properly. On that architecture, I'm willing to bet that doubles need to be aligned on a 4-byte or 8-byte boundary.

The Sparc ABI requires that doubles be aligned on a 4-byte boundary. However, gcc uses instructions which require 8-byte alignment of doubles on SPARC by default - there are a couple of flags which can be used to force 4-byte alignment, but that imposes a (usually significant) speed penalty. AFAIK, the Solaris compilers also require 8-byte alignment for doubles.

In [4]: from numpy import dtype

In [5]: dtype([('i',int), ('s','|S3'), ('f',float)]).fields.items() Out[5]: [('i', (dtype('int32'), 0)), ('s', (dtype('|S3'), 4)), ('f', (dtype('float64'), 7))]

...

...

os.uname()[4] 'sparc64' from numpy import dtype dtype([('i',int), ('s','|S3'), ('f',float)]).fields.items()

[('i', (dtype('int32'), 0)), ('s', (dtype('|S3'), 4)), ('f', (dtype('float64'), 7))] -- Neil Muller drnlmuller@gmail.com I've got a gmail account. Why haven't I become cool?