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.

* 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.

* 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.

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.

Mike


On Mon, Jul 22, 2013 at 5:18 PM, Juha <[email protected]> wrote:

> AVX needs support from operating system and according to Wikipedia the
> first Windows to support AVX is 7 SP1.
>
> Should the client report all the features that could be available and leave
> it to the scheduler to decide what is safe to use or should the client
> report only those features that the entire system supports?
>
> (SSEn needs OS support as well, but since that was added in Win 95 or 98
> maybe we can safely assume the support is always available.)
>
> -Juha
>
>
> On 22 July 2013 20:09, Rom Walton <[email protected]> wrote:
>
> > Done.
> >
> > Revision: 9b2d0f992f6669d31d1996c4fc105ce22324445b
> > Author: Rom Walton
> > Date: 7/22/2013 1:08:36 PM
> > Message:
> > client: Add detection of the AVX instruction set for newer processors
> >
> >
> > ----
> > Modified: client/hostinfo_win.cpp
> >
> > ----- Rom
> >
> > -----Original Message-----
> > From: boinc_dev [mailto:[email protected]] On Behalf Of
> > Wolfgang Schwieger
> > Sent: Monday, July 22, 2013 1:02 PM
> > To: 'BOINC Developers Mailing List'
> > Subject: [boinc_dev] : BOINC (windows) doesn't report avx processor
> > feature
> >
> > Hi all,
> >
> > BOINC (windows) reports these processor features for a sandy bridge CPU
> > (2600k):
> > Processor features: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
> > mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss htt tm pni
> > ssse3 cx16
> > sse4_1 sse4_2 popcnt aes syscall nx lm vmx tm2 pbe
> >
> > But there is no avx entry, so PrimeGrid cannot deliver the new
> > GeneferAVX application to windows hosts.
> >
> > Can you please add this line to hostinfo_win.cpp (e.g. line 1075)?
> >
> > FEATURE_TEST(std_supported, (std_ecx & (1 << 28)), "avx ");
> >
> >
> > Regards
> > Wolfgang Schwieger
> >
> >
> >
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