Messages in this thread | | | Date | Wed, 2 Dec 2020 15:32:13 -0500 | From | Tejun Heo <> | Subject | Re: [RFC PATCH] blk-iocost: Optimize the ioc_refreash_vrate() function |
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On Sun, Nov 29, 2020 at 10:37:18AM +0800, Baolin Wang wrote: > The ioc_refreash_vrate() will only be called in ioc_timer_fn() after > starting a new period or stopping the period. > > So when starting a new period, the variable 'pleft' in ioc_refreash_vrate() > is always the period's time, which means if the abs(ioc->vtime_err) > is less than the period's time, the vcomp is 0, and we do not need > compensate the vtime_rate in this case, just set it as the base vrate > and return. > > When stopping the period, the ioc->vtime_err will be cleared to 0, > and we also do not need to compensate the vtime_rate, just set it as > the base vrate and return.
Before, the function did something which is conceptually discrete and describable. After, its operation is intertwined with when it's called. I don't think this sort of micro optimizations are beneficial in cold paths.
Thanks.
-- tejun
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