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[Qemu-devel] [PULL 04/15] include/processor.h: define cpu_relax()
From: |
Richard Henderson |
Subject: |
[Qemu-devel] [PULL 04/15] include/processor.h: define cpu_relax() |
Date: |
Fri, 10 Jun 2016 07:26:42 -0700 |
From: "Emilio G. Cota" <address@hidden>
Taken from the linux kernel.
Reviewed-by: Sergey Fedorov <address@hidden>
Reviewed-by: Richard Henderson <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
Signed-off-by: Emilio G. Cota <address@hidden>
Message-Id: <address@hidden>
Signed-off-by: Richard Henderson <address@hidden>
---
include/qemu/processor.h | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 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..42bcc99
--- /dev/null
+++ b/include/qemu/processor.h
@@ -0,0 +1,30 @@
+/*
+ * Copyright (C) 2016, Emilio G. Cota <address@hidden>
+ *
+ * License: GNU GPL, version 2.
+ * See the COPYING file in the top-level directory.
+ */
+#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")
+
+#elif defined(__ia64__)
+# define cpu_relax() asm volatile("hint @pause" ::: "memory")
+
+#elif defined(__aarch64__)
+# define cpu_relax() asm volatile("yield" ::: "memory")
+
+#elif 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")
+
+#else
+# define cpu_relax() barrier()
+#endif
+
+#endif /* QEMU_PROCESSOR_H */
--
2.5.5
- [Qemu-devel] [PULL 00/15] tb hash improvements, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 03/15] seqlock: rename write_lock/unlock to write_begin/end, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 02/15] seqlock: remove optional mutex, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 07/15] tb hash: hash phys_pc, pc, and flags with xxhash, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 04/15] include/processor.h: define cpu_relax(),
Richard Henderson <=
- [Qemu-devel] [PULL 05/15] qemu-thread: add simple test-and-set spinlock, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 06/15] exec: add tb_hash_func5, derived from xxhash, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 01/15] compiler.h: add QEMU_ALIGNED() to enforce struct alignment, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 09/15] qdist: add test program, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 13/15] qht: add test-qht-par to invoke qht-bench from 'check' target, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 12/15] qht: add qht-bench, a performance benchmark, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 15/15] translate-all: add tb hash bucket info to 'info jit' dump, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 14/15] tb hash: track translated blocks with qht, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 08/15] qdist: add module to represent frequency distributions of data, Richard Henderson, 2016/06/10
- [Qemu-devel] [PULL 11/15] qht: add test program, Richard Henderson, 2016/06/10