diff options
| author | Vojtech Pavlik <vojtech@suse.cz> | 2006-09-26 12:52:28 +0400 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-09-26 12:52:28 +0400 |
| commit | c08c820508233b424deab3302bc404bbecc6493a (patch) | |
| tree | d6ed79fb2d03513f6c71fc7e47705c4a19512f53 /include/linux | |
| parent | a670fad0adb1cc6202a607d250f10bd380593905 (diff) | |
| download | linux-c08c820508233b424deab3302bc404bbecc6493a.tar.xz | |
[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')
| -rw-r--r-- | include/linux/getcpu.h | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/include/linux/getcpu.h b/include/linux/getcpu.h new file mode 100644 index 000000000000..031ed3780e45 --- /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 Results might be upto a jiffie + out of date, but will be faster.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 |