On Tue, Jun 5, 2018 at 4:20 PM Alexey Dobriyan wrote:
>
> This is Broadwell Xeon E5-2620 v4.
> Which is somewhat strange indeed because it should be modern enough.
Yeah, odd.
Here's the benchmark I used:
#define SIZE 4068
int main(int argc, char **argv)
{
int i;
unsigned char
On Tue, Jun 5, 2018 at 4:20 PM Alexey Dobriyan wrote:
>
> This is Broadwell Xeon E5-2620 v4.
> Which is somewhat strange indeed because it should be modern enough.
Yeah, odd.
Here's the benchmark I used:
#define SIZE 4068
int main(int argc, char **argv)
{
int i;
unsigned char
On Tue, Jun 05, 2018 at 04:04:37PM -0700, Linus Torvalds wrote:
> On Tue, Jun 5, 2018 at 4:01 PM Linus Torvalds
> wrote:
> >
> > On Tue, Jun 5, 2018 at 3:41 PM Alexey Dobriyan wrote:
> > >
> > > On my potato performance increase is 33%, sheesh.
> > > And CPU starts doing 3 instructions per cycle
On Tue, Jun 05, 2018 at 04:04:37PM -0700, Linus Torvalds wrote:
> On Tue, Jun 5, 2018 at 4:01 PM Linus Torvalds
> wrote:
> >
> > On Tue, Jun 5, 2018 at 3:41 PM Alexey Dobriyan wrote:
> > >
> > > On my potato performance increase is 33%, sheesh.
> > > And CPU starts doing 3 instructions per cycle
On Tue, Jun 5, 2018 at 4:01 PM Linus Torvalds
wrote:
>
> On Tue, Jun 5, 2018 at 3:41 PM Alexey Dobriyan wrote:
> >
> > On my potato performance increase is 33%, sheesh.
> > And CPU starts doing 3 instructions per cycle vs 2.
>
> Whee. That's a shockingly big difference. On my CPU (i7-6700K) it
>
On Tue, Jun 5, 2018 at 4:01 PM Linus Torvalds
wrote:
>
> On Tue, Jun 5, 2018 at 3:41 PM Alexey Dobriyan wrote:
> >
> > On my potato performance increase is 33%, sheesh.
> > And CPU starts doing 3 instructions per cycle vs 2.
>
> Whee. That's a shockingly big difference. On my CPU (i7-6700K) it
>
On Tue, Jun 5, 2018 at 3:41 PM Alexey Dobriyan wrote:
>
> On my potato performance increase is 33%, sheesh.
> And CPU starts doing 3 instructions per cycle vs 2.
Whee. That's a shockingly big difference. On my CPU (i7-6700K) it
makes absolutely no difference whether the values are integers or in
On Tue, Jun 5, 2018 at 3:41 PM Alexey Dobriyan wrote:
>
> On my potato performance increase is 33%, sheesh.
> And CPU starts doing 3 instructions per cycle vs 2.
Whee. That's a shockingly big difference. On my CPU (i7-6700K) it
makes absolutely no difference whether the values are integers or in
On Tue, Jun 05, 2018 at 10:32:55AM -0700, Linus Torvalds wrote:
> On Tue, Jun 5, 2018 at 10:22 AM Alexey Dobriyan wrote:
> >
> > Tested? :^) I had P4 maybe ~15(?) years ago.
>
> Did you EVEN test it on what you have today?
>
> Do you have any numbers at all, in other words?
>
>
On Tue, Jun 05, 2018 at 10:32:55AM -0700, Linus Torvalds wrote:
> On Tue, Jun 5, 2018 at 10:22 AM Alexey Dobriyan wrote:
> >
> > Tested? :^) I had P4 maybe ~15(?) years ago.
>
> Did you EVEN test it on what you have today?
>
> Do you have any numbers at all, in other words?
>
>
On Tue, Jun 5, 2018 at 10:22 AM Alexey Dobriyan wrote:
>
> Tested? :^) I had P4 maybe ~15(?) years ago.
Did you EVEN test it on what you have today?
Do you have any numbers at all, in other words?
Micro-optimizations need numbers. Otherwise they aren't
micro-optimizations, they are just
On Tue, Jun 5, 2018 at 10:22 AM Alexey Dobriyan wrote:
>
> Tested? :^) I had P4 maybe ~15(?) years ago.
Did you EVEN test it on what you have today?
Do you have any numbers at all, in other words?
Micro-optimizations need numbers. Otherwise they aren't
micro-optimizations, they are just
On Tue, Jun 05, 2018 at 05:05:14PM +0200, Ingo Molnar wrote:
>
> * Linus Torvalds wrote:
>
> > On Mon, Jun 4, 2018 at 5:21 AM Ingo Molnar wrote:
> > >
> > > - __clear_user() micro-optimization (Alexey Dobriyan)
> >
> > Was this actually tested?
>
> I'm not sure - Alexey?
>
> > I think one
On Tue, Jun 05, 2018 at 05:05:14PM +0200, Ingo Molnar wrote:
>
> * Linus Torvalds wrote:
>
> > On Mon, Jun 4, 2018 at 5:21 AM Ingo Molnar wrote:
> > >
> > > - __clear_user() micro-optimization (Alexey Dobriyan)
> >
> > Was this actually tested?
>
> I'm not sure - Alexey?
>
> > I think one
On Tue, Jun 5, 2018 at 8:05 AM Ingo Molnar wrote:
>
> Ok, fair point and agreed - if Alexey sends some measurements to back the
> change
> I'll keep this, otherwise queue up a revert.
I don't think it needs to be reverted, it's not like it's likely to
hurt on any modern CPU's. The issues I
On Tue, Jun 5, 2018 at 8:05 AM Ingo Molnar wrote:
>
> Ok, fair point and agreed - if Alexey sends some measurements to back the
> change
> I'll keep this, otherwise queue up a revert.
I don't think it needs to be reverted, it's not like it's likely to
hurt on any modern CPU's. The issues I
* Linus Torvalds wrote:
> On Mon, Jun 4, 2018 at 5:21 AM Ingo Molnar wrote:
> >
> > - __clear_user() micro-optimization (Alexey Dobriyan)
>
> Was this actually tested?
I'm not sure - Alexey?
> I think one reason people avoided the constant was that on some
> microarchitecture it ended up
* Linus Torvalds wrote:
> On Mon, Jun 4, 2018 at 5:21 AM Ingo Molnar wrote:
> >
> > - __clear_user() micro-optimization (Alexey Dobriyan)
>
> Was this actually tested?
I'm not sure - Alexey?
> I think one reason people avoided the constant was that on some
> microarchitecture it ended up
On Mon, Jun 4, 2018 at 5:21 AM Ingo Molnar wrote:
>
> - __clear_user() micro-optimization (Alexey Dobriyan)
Was this actually tested?
I think one reason people avoided the constant was that on some
microarchitecture it ended up being a separate uop just for the
constant generation, because it
On Mon, Jun 4, 2018 at 5:21 AM Ingo Molnar wrote:
>
> - __clear_user() micro-optimization (Alexey Dobriyan)
Was this actually tested?
I think one reason people avoided the constant was that on some
microarchitecture it ended up being a separate uop just for the
constant generation, because it
Linus,
Please pull the latest x86-asm-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-asm-for-linus
# HEAD: 6469a0ee0a06b2ea1f5afbb1d5a3feed017d4c7a x86/io: Define
readq()/writeq() to use 64-bit type
Two smaller changes:
- better support
Linus,
Please pull the latest x86-asm-for-linus git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git x86-asm-for-linus
# HEAD: 6469a0ee0a06b2ea1f5afbb1d5a3feed017d4c7a x86/io: Define
readq()/writeq() to use 64-bit type
Two smaller changes:
- better support
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