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authorVojtech Pavlik <vojtech@suse.cz>2006-09-26 10:52:28 +0200
committerAndi Kleen <andi@basil.nowhere.org>2006-09-26 10:52:28 +0200
commitc08c820508233b424deab3302bc404bbecc6493a (patch)
treed6ed79fb2d03513f6c71fc7e47705c4a19512f53 /include/linux/getcpu.h
parenta670fad0adb1cc6202a607d250f10bd380593905 (diff)
downloadop-kernel-dev-c08c820508233b424deab3302bc404bbecc6493a.zip
op-kernel-dev-c08c820508233b424deab3302bc404bbecc6493a.tar.gz
[PATCH] Add the vgetcpu vsyscall
This patch adds a vgetcpu vsyscall, which depending on the CPU RDTSCP capability uses either the RDTSCP or CPUID to obtain a CPU and node numbers and pass them to the program. AK: Lots of changes over Vojtech's original code: Better prototype for vgetcpu() It's better to pass the cpu / node numbers as separate arguments to avoid mistakes when going from SMP to NUMA. Also add a fast time stamp based cache using a user supplied argument to speed things more up. Use fast method from Chuck Ebbert to retrieve node/cpu from GDT limit instead of CPUID Made sure RDTSCP init is always executed after node is known. Drop printk Signed-off-by: Vojtech Pavlik <vojtech@suse.cz> Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'include/linux/getcpu.h')
-rw-r--r--include/linux/getcpu.h16
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/getcpu.h b/include/linux/getcpu.h
new file mode 100644
index 0000000..031ed37
--- /dev/null
+++ b/include/linux/getcpu.h
@@ -0,0 +1,16 @@
+#ifndef _LINUX_GETCPU_H
+#define _LINUX_GETCPU_H 1
+
+/* Cache for getcpu() to speed it up. Results might be upto a jiffie
+ out of date, but will be faster.
+ User programs should not refer to the contents of this structure.
+ It is only a cache for vgetcpu(). It might change in future kernels.
+ The user program must store this information per thread (__thread)
+ If you want 100% accurate information pass NULL instead. */
+struct getcpu_cache {
+ unsigned long t0;
+ unsigned long t1;
+ unsigned long res[4];
+};
+
+#endif
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