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Re: BENCHTESTS: memmove benchtests do not test overlapping memory regions
- From: Anton Youdkevitch <anton dot youdkevitch at bell-sw dot com>
- To: Zack Weinberg <zackw at panix dot com>
- Cc: "libc-alpha at sourceware dot org" <libc-alpha at sourceware dot org>
- Date: Wed, 13 Feb 2019 18:24:30 +0300
- Subject: Re: BENCHTESTS: memmove benchtests do not test overlapping memory regions
- References: <5C5DA585.email@example.com> <CAKCAbMiqe9RbdN=mrr-ea41+OR=bCN97hbO93P5Xar8Yf1S2Tg@mail.gmail.com>
It turned out that memmove tests do OK regarding
overlapping memory. This is just not obvious from
So, I might change the interface a bit so that it
would be clear that only one buffer is actually
used or just add a couple of comments pointing out
that two buffers here are just for the sake of
Considering the above is not going to be such big a
change can someone just push a change like this on my
On 08/2/2019 19:41, Zack Weinberg wrote:
On Fri, Feb 8, 2019 at 10:51 AM Anton Youdkevitch
The current testing framework is using two buffers
for all sorts of string benchmarks. Considering how
the buffers get allocated (using mmap with the first
argument set to 0) they can never overlap.
So, the memmove benchtest actually tests memcpy
(with a little additional startup) instead of memmove.
I would like to adapt memmove benchset to cover the
case of overlapping memory regions as well.
Yes, that would be a welcome improvement. It's probably going to be
big enough that you will need to file contributor paperwork with the
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