On Thu, Jul 17, 2008 at 10:51 AM, Robert Kern <robert.kern@gmail.com> wrote:
> On Thu, Jul 17, 2008 at 03:19, Pauli Virtanen <pav@iki.fi> 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))]