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| author | Andy Lutomirski <luto@amacapital.net> | 2015-12-10 19:20:19 -0800 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2015-12-11 08:56:02 +0100 |
| commit | 6b078f5de7fc0851af4102493c7b5bb07e49c4cb (patch) | |
| tree | 6ad59677ef65dd5ab468705dcb46019996392293 /kernel/irq/dummychip.c | |
| parent | 677a73a9aa5433ea728200c26a7b3506d5eaa92b (diff) | |
| download | op-kernel-dev-6b078f5de7fc0851af4102493c7b5bb07e49c4cb.zip op-kernel-dev-6b078f5de7fc0851af4102493c7b5bb07e49c4cb.tar.gz | |
x86, vdso, pvclock: Simplify and speed up the vdso pvclock reader
The pvclock vdso code was too abstracted to understand easily
and excessively paranoid. Simplify it for a huge speedup.
This opens the door for additional simplifications, as the vdso
no longer accesses the pvti for any vcpu other than vcpu 0.
Before, vclock_gettime using kvm-clock took about 45ns on my
machine. With this change, it takes 29ns, which is almost as
fast as the pure TSC implementation.
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-mm@kvack.org
Link: http://lkml.kernel.org/r/6b51dcc41f1b101f963945c5ec7093d72bdac429.1449702533.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel/irq/dummychip.c')
0 files changed, 0 insertions, 0 deletions
