On Fri, 24 Jun 2022 16:33:16 -0700, Paul E. McKenney wrote:
> On Sat, Jun 25, 2022 at 08:12:09AM +0900, Akira Yokosawa wrote:
>> Hi Paul,
>>
>> I find the analogy of Figure 7.11 hard to grasp.
>>
>> Whether a lock is global or per-instance, the cost of locking
>> (saw kerf) is observed only when a CPU/thread does the locking
>> operation.
>>
>> In this figure, does each board represent data elements, not a
>> CPU/thread? If this is the case, what does the waste of "saw kerf"
>> mean?
>>
>> What am I missing?
>>
>> (I hope I am clear enough on what I don't get...)
>
> It might well be that I am getting too excited about this one. ;-)
>
> Maybe I need to drop it. At the very least, I need to much more clearly
> explain it.
>
> But...
>
> Each board represents one lock. The "saw kerf" is the time lost when
> releasing that lock and someone else immediately acquiring it.
>
> Does that help?
Well then, why does the left side figure have ten boards?
Thanks, Akira
>
> Thanx, Paul
