From: Richard Henderson <rth@twiddle.net>
To: qemu-devel@nongnu.org
Cc: peter.maydell@linaro.org, "Emilio G. Cota" <cota@braap.org>
Subject: [Qemu-devel] [PULL 04/15] include/processor.h: define cpu_relax()
Date: Fri, 10 Jun 2016 07:26:42 -0700 [thread overview]
Message-ID: <1465568813-19771-5-git-send-email-rth@twiddle.net> (raw)
In-Reply-To: <1465568813-19771-1-git-send-email-rth@twiddle.net>
From: "Emilio G. Cota" <cota@braap.org>
Taken from the linux kernel.
Reviewed-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Reviewed-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1465412133-3029-5-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
---
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 <cota@braap.org>
+ *
+ * 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
next prev parent reply other threads:[~2016-06-10 14:27 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-06-10 14:26 [Qemu-devel] [PULL 00/15] tb hash improvements Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 01/15] compiler.h: add QEMU_ALIGNED() to enforce struct alignment Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 02/15] seqlock: remove optional mutex Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 03/15] seqlock: rename write_lock/unlock to write_begin/end Richard Henderson
2016-06-10 14:26 ` Richard Henderson [this message]
2016-06-10 14:26 ` [Qemu-devel] [PULL 05/15] qemu-thread: add simple test-and-set spinlock Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 06/15] exec: add tb_hash_func5, derived from xxhash Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 07/15] tb hash: hash phys_pc, pc, and flags with xxhash Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 08/15] qdist: add module to represent frequency distributions of data Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 09/15] qdist: add test program Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 10/15] qht: QEMU's fast, resizable and scalable Hash Table Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 11/15] qht: add test program Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 12/15] qht: add qht-bench, a performance benchmark Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 13/15] qht: add test-qht-par to invoke qht-bench from 'check' target Richard Henderson
2016-06-10 14:26 ` [Qemu-devel] [PULL 14/15] tb hash: track translated blocks with qht Richard Henderson
2016-08-10 13:36 ` Igor Mammedov
2016-08-10 19:25 ` [Qemu-devel] [PATCH] qht: support resetting an uninitialized qht Emilio G. Cota
2016-08-11 8:43 ` Igor Mammedov
2016-06-10 14:26 ` [Qemu-devel] [PULL 15/15] translate-all: add tb hash bucket info to 'info jit' dump Richard Henderson
2016-07-22 9:04 ` Changlong Xie
2016-07-22 16:36 ` [Qemu-devel] [PATCH] qht: do not segfault when gathering stats from an uninitialized qht Emilio G. Cota
2016-07-23 7:45 ` Paolo Bonzini
2016-07-23 10:01 ` Peter Maydell
2016-07-23 10:54 ` Paolo Bonzini
2016-07-23 23:09 ` Emilio G. Cota
2016-06-10 15:33 ` [Qemu-devel] [PULL 00/15] tb hash improvements Peter Maydell
2016-06-10 15:57 ` Peter Maydell
2016-06-10 16:34 ` Emilio G. Cota
2016-06-10 16:41 ` Peter Maydell
2016-06-10 19:24 ` Emilio G. Cota
2016-06-11 23:09 ` Richard Henderson
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