On Wed, 2015-08-05 at 14:03 +1000, Anton Blanchard wrote:
> Hi,
>
> While looking at traces of kernel workloads, I noticed places where gcc
> used a large number of non volatiles. Some of these functions
> did very little work, and we spent most of our time saving the
> non volatiles to the stack
Hi,
Here is another instruction trace from a kernel context switch trace.
Quite a lot of register and CR save/restore code.
Regards,
Anton
c02943d8 mfcrr12
c02943dc std r20,-96(r1)
c02943e0 std r21,-88(r1)
c02943e4 rldicl. r9,r4,63,63
c0294
On Tue, Aug 11, 2015 at 03:08:29PM -0500, Segher Boessenkool wrote:
> [snip code]
>
> After the prologue there are 46 insns executed before the epilogue.
> Many of those are conditional branches (that are not executed); it is
> all fall-through until it jumps to the "tail" (the few insns before
>
On Mon, Aug 10, 2015 at 02:52:28PM +1000, Anton Blanchard wrote:
> Hi Bill, Segher,
>
> > I agree with Segher. We already know we have opportunities to do a
> > better job with shrink-wrapping (pushing this kind of useless
> > activity down past early exits), so having examples of code to look
>
Hi Bill, Segher,
> I agree with Segher. We already know we have opportunities to do a
> better job with shrink-wrapping (pushing this kind of useless
> activity down past early exits), so having examples of code to look
> at to improve this would be useful.
I'll look out for specific examples. I
...@samba.org
Date: 08/05/2015 06:20 AM
Subject:Re: RFC: Reducing the number of non volatile GPRs in the ppc64
kernel
Hi Anton,
On Wed, Aug 05, 2015 at 02:03:00PM +1000, Anton Blanchard wrote:
> While looking at traces of kernel workloads, I noticed places where gcc
> used a
Hi Anton,
On Wed, Aug 05, 2015 at 02:03:00PM +1000, Anton Blanchard wrote:
> While looking at traces of kernel workloads, I noticed places where gcc
> used a large number of non volatiles. Some of these functions
> did very little work, and we spent most of our time saving the
> non volatiles to t
Hi,
While looking at traces of kernel workloads, I noticed places where gcc
used a large number of non volatiles. Some of these functions
did very little work, and we spent most of our time saving the
non volatiles to the stack and reading them back.
It made me wonder if we have the right ratio o
