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authorAlok Kataria <akataria@vmware.com>2008-06-20 15:06:33 -0700
committerIngo Molnar <mingo@elte.hu>2008-06-23 22:51:33 +0200
commit3da757daf86e498872855f0b5e101f763ba79499 (patch)
treebffffafed7322c66a1b886b661cfd8a8a7f5a924 /include/linux/delay.h
parente01b70ef3eb3080fecc35e15f68cd274c0a48163 (diff)
x86: use cpu_khz for loops_per_jiffy calculation
On the x86 platform we can use the value of tsc_khz computed during tsc calibration to calculate the loops_per_jiffy value. Its very important to keep the error in lpj values to minimum as any error in that may result in kernel panic in check_timer. In virtualization environment, On a highly overloaded host the guest delay calibration may sometimes result in errors beyond the ~50% that timer_irq_works can handle, resulting in the guest panicking. Does some formating changes to lpj_setup code to now have a single printk to print the bogomips value. We do this only for the boot processor because the AP's can have different base frequencies or the BIOS might boot a AP at a different frequency. Signed-off-by: Alok N Kataria <akataria@vmware.com> Cc: Arjan van de Ven <arjan@infradead.org> Cc: Daniel Hecht <dhecht@vmware.com> Cc: Tim Mann <mann@vmware.com> Cc: Zach Amsden <zach@vmware.com> Cc: Sahil Rihan <srihan@vmware.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'include/linux/delay.h')
-rw-r--r--include/linux/delay.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/delay.h b/include/linux/delay.h
index 54552d21296e..01aec60590ab 100644
--- a/include/linux/delay.h
+++ b/include/linux/delay.h
@@ -41,6 +41,7 @@ static inline void ndelay(unsigned long x)
#define ndelay(x) ndelay(x)
#endif
+extern unsigned long lpj_tsc;
void calibrate_delay(void);
void msleep(unsigned int msecs);
unsigned long msleep_interruptible(unsigned int msecs);