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Date:   Tue, 26 Oct 2021 21:15:11 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Kalesh Singh <kaleshsingh@google.com>
Cc:     surenb@google.com, hridya@google.com, namhyung@kernel.org,
        kernel-team@android.com, Jonathan Corbet <corbet@lwn.net>,
        Ingo Molnar <mingo@redhat.com>, Shuah Khan <shuah@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Tom Zanussi <zanussi@kernel.org>, linux-doc@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: Re: [PATCH v4 6/8] tracing/histogram: Optimize division by a power
 of 2
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On Tue, 26 Oct 2021 18:09:22 -0700
Kalesh Singh <kaleshsingh@google.com> 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