From: Joseph Myers <joseph@codesourcery.com>
To: Szabolcs Nagy <szabolcs.nagy@arm.com>
Cc: GNU C Library <libc-alpha@sourceware.org>, <nd@arm.com>
Subject: Re: [PATCH 4/6] Add new log2 implementation
Date: Wed, 27 Jun 2018 15:47:00 -0000 [thread overview]
Message-ID: <alpine.DEB.2.20.1806271542050.17687@digraph.polyomino.org.uk> (raw)
In-Reply-To: <77536c53-496b-9b8b-88fd-f7bf4312c1c2@arm.com>
On Wed, 27 Jun 2018, Szabolcs Nagy wrote:
> Improvements on Cortex-A72 compared to current glibc master:
> latency: 2.0x
> thruput: 1.9x
Could you clarify this testing more? If you were testing on AArch64, this
patch should have resulted in no changes at all to performance, because
AArch64 uses sysdeps/ieee754/dbl-64/wordsize-64/e_log2.c and you're not
changing or removing the wordsize-64 version in this patch.
(I expect it would make sense for this patch to remove the wordsize-64
version. Generically, it might make sense to see if the dbl-64 functions
are actually any better for 32-bit systems than the dbl-64/wordsize-64
versions - if GCC is good enough at generating code for the wordsize-64
versions on 32-bit systems, reducing the number of variants by using some
or all of the wordsize-64 versions also on 32-bit systems might make
sense.)
--
Joseph S. Myers
joseph@codesourcery.com
next prev parent reply other threads:[~2018-06-27 15:47 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-27 14:54 Szabolcs Nagy
2018-06-27 15:47 ` Joseph Myers [this message]
2018-06-27 16:06 ` Szabolcs Nagy
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