Re: [PATCH v4 6/8] tracing/histogram: Optimize division by a power of 2

From: Steven Rostedt
Date: Tue Oct 26 2021 - 21:15:17 EST


On Tue, 26 Oct 2021 18:09:22 -0700
Kalesh Singh <kaleshsingh@xxxxxxxxxx> wrote:

> > delta = mult * div / 2^20
> >
> > That is if mult is a power of two, then there would be no rounding
> > errors, and the delta is zero, making the max infinite:

That should have been (as shown in the algorithm)

delta = mult * div - 2 ^ 20

As mult is 2^20 / div; and the above should end up zero if there's no
rounding issues, as it would be:

delta = (2^20 / div) * div - 2^20

-- Steve