RE: [Scst-devel] [Iscsitarget-devel] ISCSI-SCST performance (with also IET and STGT data)

Ross S. W. Walker
2009-04-02T14:15:00Z

Ross S. W. Walker wrote:
> Vladislav Bolkhovitin wrote:
> > Vladislav Bolkhovitin, on 04/02/2009 11:38 AM wrote:
> > > James Bottomley, on 04/02/2009 12:23 AM wrote:
> > >>
> > >> SCST explicitly fiddles with the io context to get this to happen. It
> > >> has a hack to block to export alloc_io_context:
> > >>
> > >> http://marc.info/?t=122893564800003
> > >
> > > Correct, although I wouldn't call it "fiddle", rather "grouping" ;)
>
> Call it what you like,
>
> Vladislav Bolkhovitin wrote:
> > Ross S. W. Walker, on 03/30/2009 10:33 PM wrote:
> >
> > I would be interested in knowing how your code defeats CFQ's extremely
> > high latency? Does your code reach into the io scheduler too? If not,
> > some code hints would be great.
>

The above quoting was wrong, for accuracy, it should have read:

Vladislav Bolkhovitin wrote:
> Ross S. W. Walker, on 03/30/2009 10:33 PM wrote:
> >
> > I would be interested in knowing how your code defeats CFQ's extremely
> > high latency? Does your code reach into the io scheduler too? If not,
> > some code hints would be great.
>
> Hmm, CFQ doesn't have any extra processing latency, especially
> "extremely", hence there is nothing to defeat. If it had, how could it
> been chosen as the default?

Just so there is no misunderstanding who said what here.

-Ross

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