Messages in this thread | | | Date | Wed, 24 Aug 2011 11:16:03 +0800 | From | Wu Fengguang <> | Subject | Re: [PATCH 2/5] writeback: dirty position control |
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> > > > + x_intercept = setpoint + 2 * span; > ^^ BTW, why do you have 2*span here? It can result in x_intercept being > ~3*bdi_thresh... So maybe you should use bdi_thresh/2 in the computation of > span?
OK, I'll follow your suggestion to use
span = 8 * write_bw, for single bdi case span = bdi_thresh, for JBOD case x_intercept = setpoint + span;
It does make sense to squeeze the bdi_dirty fluctuation range a bit by doubling span and making the control line more sharp.
Thanks, Fengguang
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