From: Joe Perches <joe@perches.com>
To: Michael Davidson <md@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
David Miller <davem@davemloft.net>,
Matthew Wilcox <mawilcox@microsoft.com>,
Kees Cook <keescook@chromium.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] lib/int_sqrt.c: optimize for small argument values
Date: Thu, 19 Oct 2017 23:13:47 -0700 [thread overview]
Message-ID: <1508480027.6806.44.camel@perches.com> (raw)
In-Reply-To: <20171019203137.131042-1-md@google.com>
On Thu, 2017-10-19 at 13:31 -0700, Michael Davidson wrote:
> int_sqrt() currently takes approximately constant time
> regardless of the value of the argument. By using the
> magnitude of the operand to set the initial conditions
> for the calculation the cost becomes proportional to
> log2 of the argument with the worst case behavior not
> being measurably slower than it currently is.
https://lkml.org/lkml/2017/7/24/408
next prev parent reply other threads:[~2017-10-20 6:13 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-19 20:31 [PATCH] lib/int_sqrt.c: optimize for small argument values Michael Davidson
2017-10-19 20:42 ` Kees Cook
2017-10-19 20:56 ` Jason A. Donenfeld
2017-10-19 21:04 ` Kees Cook
2017-10-20 6:13 ` Joe Perches [this message]
2017-10-20 14:18 ` Kees Cook
2017-10-20 16:22 ` Peter Zijlstra
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