[coreboot] [PATCH 3/4] Reduce TSC calibrations from 20ms to 2ms.

Kevin O'Connor kevin at koconnor.net
Tue Sep 7 01:24:11 CEST 2010


2ms is enough time to accurately obtain the clock rate.

Signed-off-by: Kevin O'Connor <kevin at koconnor.net>
---
 src/cpu/x86/tsc/delay_tsc.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/cpu/x86/tsc/delay_tsc.c b/src/cpu/x86/tsc/delay_tsc.c
index 27c89e3..1127867 100644
--- a/src/cpu/x86/tsc/delay_tsc.c
+++ b/src/cpu/x86/tsc/delay_tsc.c
@@ -18,8 +18,8 @@ static unsigned long clocks_per_usec;
  * device.
  */
 
-#define CALIBRATE_INTERVAL ((20*CLOCK_TICK_RATE)/1000) /* 20ms */
-#define CALIBRATE_DIVISOR  (20*1000) /* 20ms / 20000 == 1usec */
+#define CALIBRATE_INTERVAL ((2*CLOCK_TICK_RATE)/1000) /* 2ms */
+#define CALIBRATE_DIVISOR  (2*1000) /* 2ms / 2000 == 1usec */
 
 static unsigned long long calibrate_tsc(void)
 {
-- 
1.7.2.2





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