From: Joe Landman <joe.landman@gmail.com>
To: Sage Weil <sweil@redhat.com>
Cc: Thorsten Behrens <tbehrens@suse.com>, ceph-devel@vger.kernel.org
Subject: Re: crush: straw is dead, long live straw2
Date: Fri, 12 Dec 2014 13:18:57 -0500 [thread overview]
Message-ID: <548B3191.4040605@gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.00.1412120814050.23559@cobra.newdream.net>
On 12/12/2014 11:20 AM, Sage Weil wrote:
> We can't use floating point. The code needs to run in the kernel. We
> also need the rseults to be perfectly deterministic and consistent
> across all architectures; I'm not sure if all floating point
> implementations (and log implementations) will do that?
Have a look at this (using the code I pointed to before):
https://gist.github.com/joelandman/ec6f3abef9bc5f1c7b0e
Running on my desktop box, library double function (with casts) is about
3x slower than the local log_2 version.
next prev parent reply other threads:[~2014-12-12 18:19 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-08 23:48 crush: straw is dead, long live straw2 Sage Weil
2014-12-09 0:21 ` Josh Durgin
2014-12-12 9:14 ` Thorsten Behrens
2014-12-12 14:46 ` Sage Weil
2014-12-12 15:39 ` Joe Landman
2014-12-12 16:20 ` Sage Weil
2014-12-12 16:39 ` Joe Landman
2014-12-12 18:18 ` Joe Landman [this message]
2014-12-12 21:29 ` Sage Weil
2014-12-12 15:43 ` Milosz Tanski
2014-12-12 17:27 ` Yehuda Sadeh
2014-12-12 21:42 ` Mark Nelson
2017-01-27 0:26 ` Loic Dachary
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