Re: [Xen-devel] [PATCH] Fix clock_gettime to incrementmonotonically onPV-domain/x86

[Atsushi SAKAI <sakaia@xxxxxxxxxxxxxx>]

Hi, Keir and Jan

 Thank you for various discussions.
I rewrite it to spin_lock version.

Database software uses this kind of information.
And problematic is running OK on Native and Not on Xen

Thanks
Atsushi SAKAI



Keir Fraser <keir@xxxxxxxxxxxxx> wrote:

> Yeah, it needs a spinlock. Which is a shame, but it's still going to be much
> faster than trapping into the hypervisor, which is the only other way we're
> going to be able to achieve guaranteed monotonic time.
> 
> We could avoid the lock if we guaranteed monotonic time only per task
> (thread). Or is that not really good enough? :-)
> 
>  -- Keir
> 
> On 15/6/07 11:19, "Jan Beulich" <jbeulich@xxxxxxxxxx> wrote:
> 
> > I'm afraid this isn't MP-safe - you're in a (pseudo-)read-locked section of
> > code,
> > yet write a global variable (and even in two pieces). Jan
> > 
> >>>> Atsushi SAKAI <sakaia@xxxxxxxxxxxxxx> 15.06.07 11:47 >>>
> > Hi, Keir
> > 
> >   This patch intends to increment do_gettimeofday monotonically.
> > This is for PV-domain/x86.
> > 
> > Signed-off-by: Atsushi SAKAI <sakaia@xxxxxxxxxxxxxx>
> > 
> > By applying patch, the time rollback for SMP is fixed.
> > This is important fixes for database software.
> > 
> > Thanks
> > Atsushi SAKAI
> > 
> > 
> > 
> > _______________________________________________
> > Xen-devel mailing list
> > Xen-devel@xxxxxxxxxxxxxxxxxxx
> > http://lists.xensource.com/xen-devel
>

Attachment: fix_pvx86_timerollback_use_spinlock.patch
Description: Binary data

_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel