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Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency? |
Date: |
Mon, 15 Jun 2015 16:49:03 +0100 |
On 15 June 2015 at 16:36, Alex Züpke <address@hidden> wrote:
> So this is the way to go:
>
> --- a/target-arm/translate.c
> +++ b/target-arm/translate.c
> @@ -4084,6 +4084,7 @@ static void gen_nop_hint(DisasContext *s, int val)
> gen_set_pc_im(s, s->pc);
> s->is_jmp = DISAS_WFI;
> break;
> + case 1: /* yield */
> case 2: /* wfe */
> gen_set_pc_im(s, s->pc);
> s->is_jmp = DISAS_WFE;
Actually I want to split out the yield code path from the wfe
one, because some day we may actually implement WFE as WFE,
at which point WFE has some trap-to-EL2 logic that YIELD
doesn't. I was about to write a patch to do that...
(If you plan to run your custom OS under a hypervisor you
might prefer SEV/WFE over YIELD, because then if your custom OS
is under heavy load the hypervisor has a chance to swap this
vcpu out and run some other one.)
thanks
-- PMM
- Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?, (continued)
- Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?, Peter Maydell, 2015/06/16
- Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?, Peter Maydell, 2015/06/16
- Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?, Alex Züpke, 2015/06/16
- Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?, Peter Maydell, 2015/06/16
- Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?, Alex Züpke, 2015/06/16
- Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?, Peter Maydell, 2015/06/19
Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?, Peter Maydell, 2015/06/15
Re: [Qemu-devel] QEMU ARM SMP: IPI delivery delayed until next main loop event // how to improve IPI latency?, Paolo Bonzini, 2015/06/19