while(ticks == jiffies); will spin until either ticks or jiffies changes. Presumably ticks; is this declared external, or accessed by outside functions?
On Sun, Apr 4, 2010 at 4:19 AM, Velocity <[email protected]> wrote: > > I will quote the important lines of code that I think are confusing me > and explain the aspects of them that I think I don't understand. > init/calibrate.c > > [code]loops_per_jiffy = (1 << 12); /* Initial approximation = 4096 */[/ > code] > The choice of number 4096 > power of 2 that is 12 why is that choosen. > > Secondly > http://lxr.linux.no/#linux+v2.6.33/init/calibrate.c#L54 > In comments it is mentioning > > So, we do > * 1. pre_start <- When we are sure that jiffy switch hasn't happened > * 2. check jiffy switch > * 3. start <- timer value before or after jiffy switch > * 4. post_start <- When we are sure that jiffy switch has happened > What is all that pre_start and why is it needed to be used over here? > > Here is some thing which I am wondering not because of logic in same > program > while (ticks == jiffies);/* Wait till the start of next jiffy */ > > Till the start of next jiffy what is the processor busy with or how is > the delay introduced here?Not the mathematical calculation for udelay > or ndelay. > May be I am not clear with what I should search for.? > > -- > You received this message because you are subscribed to the Linux Users > Group. > To post a message, send email to [email protected] > To unsubscribe, send email to [email protected] > For more options, visit our group at > http://groups.google.com/group/linuxusersgroup -- Daniel -- You received this message because you are subscribed to the Linux Users Group. To post a message, send email to [email protected] To unsubscribe, send email to [email protected] For more options, visit our group at http://groups.google.com/group/linuxusersgroup To unsubscribe, reply using "remove me" as the subject.
