Commit graph

5 commits

Author SHA1 Message Date
Ingo Molnar
4fcc50abdf x86: clean up vget_cycles()
Impact: remove unused variable

I forgot to remove the now unused "cycles_t cycles" parameter from
vget_cycles() - which triggers build warnings as tsc.h is included
in a number of files.

Remove it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-09 21:05:43 +01:00
Ingo Molnar
cb9e35dce9 x86: clean up rdtsc_barrier() use
Impact: cleanup

Move rdtsc_barrier() use to vsyscall_64.c where it's relied on,
and point out its role in the context of its use.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-08 20:27:00 +01:00
Ingo Molnar
0d12cdd5f8 sched: improve sched_clock() performance
in scheduler-intense workloads native_read_tsc() overhead accounts for
20% of the system overhead:

 659567 system_call                              41222.9375
 686796 schedule                                 435.7843
 718382 __switch_to                              665.1685
 823875 switch_mm                                4526.7857
 1883122 native_read_tsc                          55385.9412
 9761990 total                                      2.8468

this is large part due to the rdtsc_barrier() that is done before
and after reading the TSC.

But sched_clock() is not a precise clock in the GTOD sense, using such
barriers is completely pointless. So remove the barriers and only use
them in vget_cycles().

This improves lat_ctx performance by about 5%.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-11-08 16:48:19 +01:00
H. Peter Anvin
1965aae3c9 x86: Fix ASM_X86__ header guards
Change header guards named "ASM_X86__*" to "_ASM_X86_*" since:

a. the double underscore is ugly and pointless.
b. no leading underscore violates namespace constraints.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-22 22:55:23 -07:00
Al Viro
bb8985586b x86, um: ... and asm-x86 move
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-22 22:55:20 -07:00
Renamed from include/asm-x86/tsc.h (Browse further)