Maybe I am to stupid to understand what's going on, but.....
BOINC reports a cpu feature (AVX) which the cpu has/or has not. (that is
what we need!)
BOINC !_also_! reports the OS, the OS version/kernel version, !_and_! the
installed service pack (for windows).
So, if a project has an application with AVX code, the project (!!!) has to
decide if/or if not this application will run under an "older" OS.
BOINC just reports the feature, the project admin configures what has to be
configured.
Wolfgang
-----Ursprüngliche Nachricht-----
Von: Juha [mailto:[email protected]]
Gesendet: Dienstag, 23. Juli 2013 22:58
An: BOINC Developers Mailing List
Betreff: Re: [boinc_dev] [SPAM] Re: : BOINC (windows) doesn't report avx
processor feature
On 23 July 2013 04:41, Michael Goetz <[email protected]> wrote:
I'm not very worried about lock of OS support for AVX, at least as far
as PrimeGrid is concerned.
* It's unlikely anyone has bought a pre-configured computer with an
AVX capable CPU that came with a version of Windows that doesn't support
AVX.
* People who built their own systems and loaded XP?!?! on it are
certainly able to load and run Linux if they wish to, and if they
loaded Win 7 without SP1 they can load SP1.
* It's unclear to me why anyone would buy, sell, or build a computer
with an AVX CPU with an operating system that doesn't support the
instruction set. It's possible, but unlikely.
Well, someone could have upgraded to a newer CPU, or replaced a broken
component without upgrading the OS at the same time. Or they might be stuck
with an older OS because they have some device for which there's drivers
only for, say, XP. Or they are forced for some other reasons to keep using
an older OS. There are reasons once you start looking for them.
And even if none of those hold, people still have the right to be silly and
keep using XP.
* There's about a 40% increase in speed with the AVX version of that
application, so if there's anyone participating in that subproject
with such a computer, they probably will want to upgrade or switch
their OS to take advantage of the increased performance.
That's a very nice speed-up. But you are assuming that:
1. People are paying attention (to such details). Maybe at PrimeGrid that's
true but I doubt that's true generally speaking. At least at Seti@homethere
are people turning in thousands and thousands of invalids so obviously they
don't pay any attention to what their computer does.
2. People are buying or configuring their systems to crunch numbers. True
for some people but I think the majority buys computers for some other
reason and install BOINC to have something for the computer to do while
they
read their emails.
* After all that, if there's actually someone who wants to run their
fancy new CPU with an OS that cripples its capabilities, I can always
change the plan class to restrict the OS to versions that do support AVX.
There's one problem with that approach. Every project that releases AVX
application would need to add those restrictions. Wasn't BOINC supposed to
handle everything that's common to all projects so that projects can then
concentrate on doing whatever science they do? So IMHO reliable information
of host's capabilities is something that BOINC should provide, one way or
the other.
So either the client should report only those processor features that the
OS
supports or the scheduler should have a function does_host_support_avx()
that checks both the reported features and the OS version.
(Generally speaking. There's one benefit for the server side check. If the
host has support for feature X in hardware but not in software, the server
could tell the user "Your host has support for feature X and we have an
application that can take advantage of it. But you need to install Y
first."
Similar to what the server currently does with at least NVIDIA
drivers.)
In short, while this is a theoretical problem, I don't think the lack of
AVX support in old versions of Windows is a significant real world
problem.
That may very well be true, but I still see it as something that could be
done better, if not even as a bug.
-Juha
