Messages in this thread |  | | Date | Tue, 8 Jan 2013 11:42:26 -0500 | From | Vivek Goyal <> | Subject | Re: [PATCH 14/24] cfq-iosched: convert cfq_group_slice() to use cfqg->vfraction |
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On Fri, Dec 28, 2012 at 12:35:36PM -0800, Tejun Heo wrote: > cfq_group_slice() calculates slice by taking a fraction of > cfq_target_latency according to the ratio of cfqg->weight against > service_tree->total_weight. This currently works only because all > cfqgs are treated to be at the same level. > > To prepare for proper hierarchy support, convert cfq_group_slice() to > base the calculation on cfqg->vfraction. As cfqg->vfraction is always > a fraction of 1 and represents the fraction allocated to the cfqg with > hierarchy considered, the slice can be simply calculated by > multiplying cfqg->vfraction to cfq_target_latency (with fixed point > shift factored in). > > As vfraction calculation currently treats all non-root cfqgs as > children of the root cfqg, this patch doesn't introduce noticeable > behavior difference. > > Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Vivek
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