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[Qemu-devel] [PATCH v3 04/11] include/processor.h: define cpu_relax()
From: |
Emilio G. Cota |
Subject: |
[Qemu-devel] [PATCH v3 04/11] include/processor.h: define cpu_relax() |
Date: |
Tue, 19 Apr 2016 19:07:43 -0400 |
Taken from the linux kernel.
Reviewed-by: Richard Henderson <address@hidden>
Signed-off-by: Emilio G. Cota <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 */
--
2.5.0
- Re: [Qemu-devel] [PATCH v3 01/11] compiler.h: add QEMU_ALIGNED() to enforce struct alignment, (continued)
- [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock, Emilio G. Cota, 2016/04/19
- Re: [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock, Richard Henderson, 2016/04/20
- Re: [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock, Emilio G. Cota, 2016/04/20
- Re: [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock, Richard Henderson, 2016/04/20
- Re: [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock, Emilio G. Cota, 2016/04/20
- Re: [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock, Richard Henderson, 2016/04/20
- Re: [Qemu-devel] [PATCH v3 05/11] qemu-thread: add simple test-and-set spinlock, Emilio G. Cota, 2016/04/21
[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 <=
[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, 2016/04/22
[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