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Re: [PATCH] benchtests/Makefile: Run the string benchmarks four times by default.
- From: "Ryan S. Arnold" <ryan dot arnold at gmail dot com>
- To: OndÅej BÃlka <neleai at seznam dot cz>
- Cc: Will Newton <will dot newton at linaro dot org>, libc-alpha <libc-alpha at sourceware dot org>, Patch Tracking <patches at linaro dot org>
- Date: Wed, 4 Sep 2013 13:22:38 -0500
- Subject: Re: [PATCH] benchtests/Makefile: Run the string benchmarks four times by default.
- Authentication-results: sourceware.org; auth=none
- References: <52274838 dot 7010902 at linaro dot org> <20130904161743 dot GA10358 at domone dot kolej dot mff dot cuni dot cz> <CANu=DmiVWFijri_iMjFGJEWdTWheHbBFOH8XULURRE8pLMkuLA at mail dot gmail dot com> <20130904165211 dot GA14906 at domone dot kolej dot mff dot cuni dot cz>
On Wed, Sep 4, 2013 at 11:52 AM, OndÅej BÃlka <neleai@seznam.cz> wrote:
> On Wed, Sep 04, 2013 at 05:20:23PM +0100, Will Newton wrote:
>> On 4 September 2013 17:17, OndÅej BÃlka <neleai@seznam.cz> wrote:
>> > On Wed, Sep 04, 2013 at 03:48:24PM +0100, Will Newton wrote:
>> >>
>> >> The string benchmarks can be affected by physical page placement, so
>> >> running them multiple times is required to account for this. Also
>> >> backup the results of the previous run like is done for the other
>> >> benchmarks.
>> >>
>> > You do not need to do this. We should instead randomize addresses used
>> > which handles this problem.
What is the objective of randomizing the addresses? What are we trying
to accomplish by different page placement?
>> That seems like it would be considerably more complicated. Do you have
>> a reason why your approach is better?
>>
> It does not matter if it is complicated, it is required to get
> reasonable results.
Your proposed solution (in a later email) is in-fact not
overly-complicated, but for the record, there is a very good reason to
avoid complexity in a project like glibc, which is already extremely
complex. Some poor soul will need to maintain all of the complicated
solutions long into the future.
Ryan