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
