| From | Andy Lutomirski <> | Subject | [PATCH v3 06/18] x86/tsc: Use the full 64-bit tsc in tsc_delay | Date | Tue, 16 Jun 2015 17:35:54 -0700 |
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As a very minor optimization, tsc_delay was only using the low 32 bits of the TSC. It's a delay function, so just use the whole thing.
Signed-off-by: Andy Lutomirski <luto@kernel.org> --- arch/x86/lib/delay.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c index 9a52ad0c0758..35115f3786a9 100644 --- a/arch/x86/lib/delay.c +++ b/arch/x86/lib/delay.c @@ -49,16 +49,16 @@ static void delay_loop(unsigned long loops) /* TSC based delay: */ static void delay_tsc(unsigned long __loops) { - u32 bclock, now, loops = __loops; + u64 bclock, now, loops = __loops; int cpu; preempt_disable(); cpu = smp_processor_id(); rdtsc_barrier(); - rdtscl(bclock); + bclock = native_read_tsc(); for (;;) { rdtsc_barrier(); - rdtscl(now); + now = native_read_tsc(); if ((now - bclock) >= loops) break; @@ -80,7 +80,7 @@ static void delay_tsc(unsigned long __loops) loops -= (now - bclock); cpu = smp_processor_id(); rdtsc_barrier(); - rdtscl(bclock); + bclock = native_read_tsc(); } } preempt_enable(); -- 2.4.2
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