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[Qemu-devel] [PATCH v4 04/14] include/processor.h: define cpu_relax()
From: |
Emilio G. Cota |
Subject: |
[Qemu-devel] [PATCH v4 04/14] include/processor.h: define cpu_relax() |
Date: |
Fri, 29 Apr 2016 23:33:07 -0400 |
Taken from the linux kernel.
Reviewed-by: Richard Henderson <address@hidden>
Reviewed-by: Alex Bennée <address@hidden>
Signed-off-by: Emilio G. Cota <address@hidden>
---
include/qemu/processor.h | 34 ++++++++++++++++++++++++++++++++++
1 file changed, 34 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..4e6a71f
--- /dev/null
+++ b/include/qemu/processor.h
@@ -0,0 +1,34 @@
+/*
+ * 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")
+#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
- [Qemu-devel] [PATCH v4 00/14] tb hash improvements, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 01/14] compiler.h: add QEMU_ALIGNED() to enforce struct alignment, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 04/14] include/processor.h: define cpu_relax(),
Emilio G. Cota <=
- [Qemu-devel] [PATCH v4 08/14] tb hash: hash phys_pc, pc, and flags with xxhash, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 03/14] seqlock: rename write_lock/unlock to write_begin/end, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 10/14] qdist: add test program, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 05/14] atomics: add atomic_test_and_set, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 11/14] qht: QEMU's fast, resizable and scalable Hash Table, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 06/14] qemu-thread: add simple test-and-set spinlock, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 14/14] translate-all: add tb hash bucket info to 'info jit' dump, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 02/14] seqlock: remove optional mutex, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 07/14] exec: add tb_hash_func5, derived from xxhash, Emilio G. Cota, 2016/04/29
- [Qemu-devel] [PATCH v4 12/14] qht: add test program, Emilio G. Cota, 2016/04/29