[Liboil] Is liboil still alive?
jsquyres at cisco.com
Fri Feb 20 08:14:10 PST 2009
On Feb 20, 2009, at 10:56 AM, Thiago Galesi wrote:
> I'm not sure about MPI but it seems two fundamentally different things
> (by reading the MPI faq).
> MPI is about distributed computing
Correct; but there's lots of things that happen locally in each
process in the overall distributed/parallel job. These kinds of local
things are what we're interested in from liboil.
> LibOIL is what the name says :) Optimized Inner Loops. It's about an
> API that provides common (vector) operations (inner product,
> multiplying all numbers in an array) and does it in the fastest way
We do have some numerical operations in MPI, and shared memory message
transports (e.g., sending messages from one process to another
transits through shared memory). So we're definitely interested in
oil_u8_copy(), for example. Some of the other operations may be
useful as well, but I haven't gotten to look closely at those yet --
my efforts so far have been with oil_u8_copy().
The general flavor of my questions are:
- Does oil_u8_copy() make non-temporal copies?
- In my benchmarking, oil_u8_copy() seems to beat gcc's memcpy() for
small sizes (e.g., <=128 bytes) for old versions of gcc (3.4.6/the
default on RHEL4) on older xeon hardware. The docs say that
oil_u8_copy() is only optimized for small sizes; so that's fine. But
using more recent hardware (e.g., woodcrest- or wolfdale-class
servers), the picture becomes much less clear about whether gcc
3.4.x's memcpy() is faster than oil_u8_copy() or not. Using other
compilers' memcpy() implementations (e.g., intel compiler, pathscale
compiler, etc.) seem to always beat oil_u8_copy(), regardless of size
and hardware. Newer gcc's (e.g., 4.3.x) also seem to always beat
oil_u8_copy(), regardless of size and hardware. My question is: is
this expected behavior? Or is there ongoing tuning occurring in
liboil for oil_u8_copy() (etc.) to try to be as fast as possible and
beat other implementations?
>> But in looking
>> through the mailing list archives, it seems that there hasn't been
>> meaningful activity since June of 2008.
>> Is the liboil project still alive? (i.e., should I bother to ask my
> I'm afraid I can't answer that question, but liboil is used in several
> projects including gstreamer, etc
Good to know.
More information about the Liboil