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Re: [Qemu-devel] [PATCH v3 04/11] include/processor.h: define cpu_relax(
From: |
Alex Bennée |
Subject: |
Re: [Qemu-devel] [PATCH v3 04/11] include/processor.h: define cpu_relax() |
Date: |
Fri, 22 Apr 2016 10:35:35 +0100 |
User-agent: |
mu4e 0.9.17; emacs 25.0.92.6 |
Emilio G. Cota <address@hidden> writes:
> Taken from the linux kernel.
>
> Reviewed-by: Richard Henderson <address@hidden>
> Signed-off-by: Emilio G. Cota <address@hidden>
License header notwithstanding:
Reviewed-by: Alex Bennée <address@hidden>
> ---
> include/qemu/processor.h | 28 ++++++++++++++++++++++++++++
> 1 file changed, 28 insertions(+)
> create mode 100644 include/qemu/processor.h
>
> diff --git a/include/qemu/processor.h b/include/qemu/processor.h
> new file mode 100644
> index 0000000..675a00a
> --- /dev/null
> +++ b/include/qemu/processor.h
> @@ -0,0 +1,28 @@
> +#ifndef QEMU_PROCESSOR_H
> +#define QEMU_PROCESSOR_H
> +
> +#include "qemu/atomic.h"
> +
> +#if defined(__i386__) || defined(__x86_64__)
> +#define cpu_relax() asm volatile("rep; nop" ::: "memory")
> +#endif
> +
> +#ifdef __ia64__
> +#define cpu_relax() asm volatile("hint @pause" ::: "memory")
> +#endif
> +
> +#ifdef __aarch64__
> +#define cpu_relax() asm volatile("yield" ::: "memory")
> +#endif
> +
> +#if defined(__powerpc64__)
> +/* set Hardware Multi-Threading (HMT) priority to low; then back to medium */
> +#define cpu_relax() asm volatile("or 1, 1, 1;"
> + "or 2, 2, 2;" ::: "memory")
> +#endif
> +
> +#ifndef cpu_relax
> +#define cpu_relax() barrier()
> +#endif
> +
> +#endif /* QEMU_PROCESSOR_H */
--
Alex Bennée
- Re: [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock, (continued)
[Qemu-devel] [UPDATED v3 05/11] qemu-thread: add simple test-and-set spinlock, Emilio G. Cota, 2016/04/20
[Qemu-devel] [PATCH v3 04/11] include/processor.h: define cpu_relax(), Emilio G. Cota, 2016/04/19
[Qemu-devel] [UPDATED v3 04/11] include/processor.h: define cpu_relax(), Emilio G. Cota, 2016/04/20
Re: [Qemu-devel] [PATCH v3 04/11] include/processor.h: define cpu_relax(),
Alex Bennée <=
[Qemu-devel] [PATCH v3 03/11] seqlock: rename write_lock/unlock to write_begin/end, Emilio G. Cota, 2016/04/19
[Qemu-devel] [PATCH v3 10/11] tb hash: track translated blocks with qht, Emilio G. Cota, 2016/04/19
[Qemu-devel] [PATCH v3 07/11] tb hash: hash phys_pc, pc, and flags with xxhash, Emilio G. Cota, 2016/04/19
[Qemu-devel] [PATCH v3 09/11] qht: add test program, Emilio G. Cota, 2016/04/19
[Qemu-devel] [PATCH v3 08/11] qht: QEMU's fast, resizable and scalable Hash Table, Emilio G. Cota, 2016/04/19