Re: [RFC][PATCH] new timeofday core subsystem (v.A0)

Christoph Lameter
2004-09-02T22:51:56Z

On Thu, 2 Sep 2004, john stultz wrote:

> What about my idea from yesterday of inverting the fastcall
> relationship? Instead of creating a structure that exports values and
> pointers the fastcall can use to create a time of day, why not use the
> fast call to read the raw time and return it back to the time of day
> code (which may be running in user context)? This avoids the duplication
> of having to re-implement the timeofday/clock_gettime functions in
> fastcall asm code.

"Read raw time"? How can you read the raw time in a fast call if the
fast call needs to do additional function calls (as defined in the
proposed time structure) in the kernel context in order to retrieve time?

A fast call cannot do any function calls in the kernel context or
otherwise.

The overhead of the function calls will reduce the performance of time
access significantly.