RE: Direct io on block device has performance regression on 2.6.x kernel

[Chen, Kenneth W]

Andi Kleen wrote on Wednesday, March 09, 2005 3:23 PM
> > Just to clarify here, these data need to be taken at grain of salt. A
> > high count in _spin_unlock_* functions do not automatically points to
> > lock contention.  It's one of the blind spot syndrome with timer based
> > profile on ia64.  There are some lock contentions in 2.6 kernel that
> > we are staring at.  Please do not misinterpret the number here.
>
> Why don't you use oprofileÂ>? It uses NMIs and can profile "inside"
> interrupt disabled sections.

The profile is taken on ia64.  we don't have nmi.  Oprofile will produce
the same result.

- Ken


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