On Sep 25, 2012, at 3:59 PM, Benjamin Herrenschmidt wrote:
> On Tue, 2012-09-25 at 15:17 +0200, Segher Boessenkool wrote:
Fine. But I believe that mfpvr emulation came first, which is the
point
I object to (see the mess that the fact that CPUID is available to
applications m
On Tue, 2012-09-25 at 15:17 +0200, Segher Boessenkool wrote:
> >> Fine. But I believe that mfpvr emulation came first, which is the
> >> point
> >> I object to (see the mess that the fact that CPUID is available to
> >> applications made to x86 when SSE registers were added).
> >
> > Heh, possibl
That's for 64-bit; another good option for 64-bit is to just never
use
isel, it hardly ever buys you anything. It is much more useful on
the
(older) 32-bit cores that support it.
Why is it more useful on 32-bit? If you're referring to the
performance of specific cores rather than some ar
Fine. But I believe that mfpvr emulation came first, which is the
point
I object to (see the mess that the fact that CPUID is available to
applications made to x86 when SSE registers were added).
Heh, possibly, I don't remember... I added the cputable, I think we
added mfpvr because we didn't
On 09/24/2012 07:47:28 PM, malc wrote:
On Tue, 25 Sep 2012, Benjamin Herrenschmidt wrote:
> On Mon, 2012-09-24 at 18:55 -0500, Scott Wood wrote:
> > The ISA says that isel is "Category: Phased-In (sV2.06)" -- are
there
> > any 2.06 chips that don't have it?
>
> I believe "malc" is interested
On Tue, 25 Sep 2012, Benjamin Herrenschmidt wrote:
> On Mon, 2012-09-24 at 18:55 -0500, Scott Wood wrote:
> > The ISA says that isel is "Category: Phased-In (sV2.06)" -- are there
> > any 2.06 chips that don't have it?
>
> I believe "malc" is interested in knowing about pre-2.06 chips that have
On 09/24/2012 07:32:03 PM, Benjamin Herrenschmidt wrote:
On Mon, 2012-09-24 at 18:55 -0500, Scott Wood wrote:
> The ISA says that isel is "Category: Phased-In (sV2.06)" -- are
there
> any 2.06 chips that don't have it?
I believe "malc" is interested in knowing about pre-2.06 chips that
have
On Mon, 2012-09-24 at 18:55 -0500, Scott Wood wrote:
> The ISA says that isel is "Category: Phased-In (sV2.06)" -- are there
> any 2.06 chips that don't have it?
I believe "malc" is interested in knowing about pre-2.06 chips that have
it.
Cheers,
Ben.
_
On 09/22/2012 08:46:06 PM, Segher Boessenkool wrote:
Have a look at /sys/kernel/debug/powerpc/emulated_instructions/
then?
Userspace should *NEVER* rely on the content of debugfs, it will
change
with time, it is not a guaranteed ABI, it's purely for people to look
at... for debugging.
mal
On Mon, 2012-09-24 at 10:06 +0200, Gabriel Paubert wrote:
> > Which we do. mfpvr is available as a fallback (essentially because if we
> > don't do it somebody's going to parse /proc/cpuinfo which is arguably
> > worse :-)
>
> Fine. But I believe that mfpvr emulation came first, which is the point
On Mon, Sep 24, 2012 at 05:58:37PM +1000, Benjamin Herrenschmidt wrote:
> On Mon, 2012-09-24 at 09:55 +0200, Gabriel Paubert wrote:
> > On Sun, Sep 23, 2012 at 03:46:06AM +0200, Segher Boessenkool wrote:
> > > Why does the kernel emulate this, btw? I can see emulation is useful
> > > for running o
On Mon, 2012-09-24 at 09:55 +0200, Gabriel Paubert wrote:
> On Sun, Sep 23, 2012 at 03:46:06AM +0200, Segher Boessenkool wrote:
> > Why does the kernel emulate this, btw? I can see emulation is useful
> > for running older binaries, for instructions that have been removed
> > from the architecture
On Sun, Sep 23, 2012 at 03:46:06AM +0200, Segher Boessenkool wrote:
> Why does the kernel emulate this, btw? I can see emulation is useful
> for running older binaries, for instructions that have been removed
> from the architecture; but for newly added instructions, or optional
> instructions, it
Have a look at /sys/kernel/debug/powerpc/emulated_instructions/ then?
Userspace should *NEVER* rely on the content of debugfs, it will
change
with time, it is not a guaranteed ABI, it's purely for people to look
at... for debugging.
malc didn't say what he wants it for... People are in use
On Sat, Sep 22, 2012 at 07:37:03PM +0400, malc wrote:
> On Sat, 22 Sep 2012, Gabriel Paubert wrote:
>
> > On Sat, Sep 22, 2012 at 02:12:42PM +0400, malc wrote:
> > > On Sat, 22 Sep 2012, Segher Boessenkool wrote:
> > >
> > > > > Is it possible to determine if _native_ isel is available from
> >
On Sun, 23 Sep 2012, Benjamin Herrenschmidt wrote:
> On Sat, 2012-09-22 at 21:08 +0200, Segher Boessenkool wrote:
> > > Thanks for suggestion, but i'd rather not play with heuristics.
> >
> > Have a look at /sys/kernel/debug/powerpc/emulated_instructions/ then?
>
> Userspace should *NEVER* rely
On Sat, 2012-09-22 at 21:08 +0200, Segher Boessenkool wrote:
> > Thanks for suggestion, but i'd rather not play with heuristics.
>
> Have a look at /sys/kernel/debug/powerpc/emulated_instructions/ then?
Userspace should *NEVER* rely on the content of debugfs, it will change
with time, it is not a
Thanks for suggestion, but i'd rather not play with heuristics.
Have a look at /sys/kernel/debug/powerpc/emulated_instructions/ then?
Segher
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On Sat, 22 Sep 2012, Gabriel Paubert wrote:
> On Sat, Sep 22, 2012 at 02:12:42PM +0400, malc wrote:
> > On Sat, 22 Sep 2012, Segher Boessenkool wrote:
> >
> > > > Is it possible to determine if _native_ isel is available from userspace
> > > > somehow?
> > >
> > > Just try to execute one and cat
On Sat, Sep 22, 2012 at 02:12:42PM +0400, malc wrote:
> On Sat, 22 Sep 2012, Segher Boessenkool wrote:
>
> > > Is it possible to determine if _native_ isel is available from userspace
> > > somehow?
> >
> > Just try to execute one and catch the SIGILL?
> >
>
> Unfortunately my kernel emulates I
On Sat, 22 Sep 2012, Segher Boessenkool wrote:
> > Is it possible to determine if _native_ isel is available from userspace
> > somehow?
>
> Just try to execute one and catch the SIGILL?
>
Unfortunately my kernel emulates ISEL for me in this case, so i don't
get any SIGILLs.
--
mailto:av1...@
Is it possible to determine if _native_ isel is available from
userspace
somehow?
Just try to execute one and catch the SIGILL?
Segher
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Hello,
Is it possible to determine if _native_ isel is available from userspace
somehow? So far my searches on the web and within kernel (headers)/glibc
were fruitless (aux vectors, cpu_user_features), few people people (Hollis
Blanchard, Richard Henderson) suggested PPC_FEATURE_ARCH_2_06, but
Po
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