Hi,
On Thu, Sep 21, 2017 at 07:34:39AM +0800, wei.guo.si...@gmail.com wrote:
> From: Simon Guo
>
> This patch add VMX primitives to do memcmp() in case the compare size
> exceeds 4K bytes.
>
> Test result with following test program(replace the "^>" with ""):
> --
I missed the exit_vmx_ops()
On Thu, 2017-09-21 at 07:34 +0800, wei.guo.si...@gmail.com wrote:
> From: Simon Guo
>
> This patch add VMX primitives to do memcmp() in case the compare size
> exceeds 4K bytes.
>
Hi Simon,
Sorry I didn't see this sooner, I've actually been working on a kernel
version of glibc commit dec4a7105
Hi Cyril,
On Sat, Sep 23, 2017 at 12:06:48AM +1000, Cyril Bur wrote:
> On Thu, 2017-09-21 at 07:34 +0800, wei.guo.si...@gmail.com wrote:
> > From: Simon Guo
> >
> > This patch add VMX primitives to do memcmp() in case the compare size
> > exceeds 4K bytes.
> >
>
> Hi Simon,
>
> Sorry I didn't
On Sun, 2017-09-24 at 05:18 +0800, Simon Guo wrote:
> Hi Cyril,
> On Sat, Sep 23, 2017 at 12:06:48AM +1000, Cyril Bur wrote:
> > On Thu, 2017-09-21 at 07:34 +0800, wei.guo.si...@gmail.com wrote:
> > > From: Simon Guo
> > >
> > > This patch add VMX primitives to do memcmp() in case the compare siz
Cyril Bur writes:
> On Sun, 2017-09-24 at 05:18 +0800, Simon Guo wrote:
>> Hi Cyril,
>> On Sat, Sep 23, 2017 at 12:06:48AM +1000, Cyril Bur wrote:
>> > On Thu, 2017-09-21 at 07:34 +0800, wei.guo.si...@gmail.com wrote:
>> > > From: Simon Guo
>> > >
>> > > This patch add VMX primitives to do memc
On Tue, Sep 26, 2017 at 03:34:36PM +1000, Michael Ellerman wrote:
> Cyril Bur writes:
> > This was written for userspace which doesn't have to explicitly enable
> > VMX in order to use it - we need to be smarter in the kernel.
>
> Well the kernel has to do it for them after a trap, which is actua
Segher Boessenkool writes:
> On Tue, Sep 26, 2017 at 03:34:36PM +1000, Michael Ellerman wrote:
>> Cyril Bur writes:
>> > This was written for userspace which doesn't have to explicitly enable
>> > VMX in order to use it - we need to be smarter in the kernel.
>>
>> Well the kernel has to do it f
On Wed, Sep 27, 2017 at 01:38:09PM +1000, Michael Ellerman wrote:
> Segher Boessenkool writes:
> > A lot of userspace code uses V*X, more and more with newer CPUs and newer
> > compiler versions. If you already paid the price for using vector
> > registers you do not need to again :-)
>
> True,
From: Segher Boessenkool
> Sent: 27 September 2017 10:28
...
> You also need nasty code to deal with the start and end of strings, with
> conditional branches and whatnot, which quickly overwhelms the benefit
> of using vector registers at all. This tradeoff also changes with newer
> ISA versions.
Hi Michael,
On Wed, Sep 27, 2017 at 01:38:09PM +1000, Michael Ellerman wrote:
> Segher Boessenkool writes:
>
> > On Tue, Sep 26, 2017 at 03:34:36PM +1000, Michael Ellerman wrote:
> >> Cyril Bur writes:
> >> > This was written for userspace which doesn't have to explicitly enable
> >> > VMX in or
On Wed, Sep 27, 2017 at 09:43:44AM +, David Laight wrote:
> From: Segher Boessenkool
> > Sent: 27 September 2017 10:28
> ...
> > You also need nasty code to deal with the start and end of strings, with
> > conditional branches and whatnot, which quickly overwhelms the benefit
> > of using vecto
From: Simon Guo
> Sent: 27 September 2017 19:34
...
> > On X86 all the AVX registers are caller saved, the system call
> > entry could issue the instruction that invalidates them all.
> > Kernel code running in the context of a user process could then
> > use the registers without saving them.
> >
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