Re: [-mm patch] x86_64 GTOD: offer scalable vgettimeofday II

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



On Thursday 01 February 2007 12:46, Ingo Molnar wrote:
> 
> * [email protected] <[email protected]> wrote:
> 
> > Inter-CPU monotonicity can not, however, be guaranteed in a vsyscall, 
> > so vsyscall is not used by default. [...]
> 
> note that this is not actually the case. My patch below, ontop of -mm, 
> implements a fully monotonic gettimeofday as an optional vsyscall 
> feature.
> 
> The 'price' paid for it is lower resolution - but it's still good for 
> those benchmarking TPC-C runs - and /alot/ simpler. 

BTW another comment: I was told that at least one of the big databases
wants ms resolution here. So to make your scheme work
would require a HZ=1024 regular interrupt. But that would also make
everything slower again due to CPU overhead as it was learned in the 2.4->2.6 HZ 
transition. 

So it might not actually be worth it.

-Andi

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux