This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: [PATCH v2] x86-64: Optimize strcmp/wcscmp with AVX2
- From: Alexander Monakov <amonakov at ispras dot ru>
- To: "H.J. Lu" <hjl dot tools at gmail dot com>
- Cc: Leonardo Sandoval <leonardo dot sandoval dot gonzalez at linux dot intel dot com>, GNU C Library <libc-alpha at sourceware dot org>
- Date: Fri, 1 Jun 2018 18:28:28 +0300 (MSK)
- Subject: Re: [PATCH v2] x86-64: Optimize strcmp/wcscmp with AVX2
- References: <20180529185339.11541-1-leonardo.sandoval.gonzalez@linux.intel.com> <CAMe9rOpKpR6pOLkxyMuTPBA1zSx4MmYYsTOwHz5pTxjdR57p1A@mail.gmail.com>
On Fri, 1 Jun 2018, H.J. Lu wrote:
> Please mention strncmp and wcsncmp in commit subject. OK with this
> change.
Many Intel CPUs reduce operating frequency upon encountering AVX code,
and some have a "spin-up" period when frequency is not yet changed and
AVX code runs at reduced throughput. Thus, why is this change not
detrimental in practice, doesn't it slow down all code (including other
programs running on the same core) as soon as a program makes a call to strcmp?
Alexander