At 3:27 PM -0700 2001-10-05, Petr Vandrovec wrote:
>On 5 Oct 01 at 14:15, Padraig Brady wrote:
>> >Another advantage of using the real time instead of a counter is that
>> >you can easily merge the both values into a single 64bit value and do
>> >arithmetic on it in user space. With a generation counter you would need
>> >to work with number pairs, which is much more complex.
>> >
>> ??
>> if (file->mtime != mtime || file->gen_count != gen_count)
>> file_changed=1;
>
>make needs comparing timestamps between two files. I cannot imagine
>how you can get this working (without network filesystem you can
>have global gen_count, but with network filesystem each server has
>its own gen_count... and using world-wide nanoseconds instead of world-wide
>gen_count looks much simpler to me ;-) )
Except for the world-wide-nanosecond-resolution synchronization problem....
Even keeping cycle-counter-based systems in sync within SMP systems
seems problematical, depending on how the counters are implemented.
-- /Jonathan Lundell. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sun Oct 07 2001 - 21:00:37 EST