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Re: [RFC] Faster memset.
- From: "Carlos O'Donell" <carlos at redhat dot com>
- To: OndÅej BÃlka <neleai at seznam dot cz>
- Cc: libc-alpha at sourceware dot org
- Date: Wed, 10 Apr 2013 15:04:38 -0400
- Subject: Re: [RFC] Faster memset.
- References: <20130323145420 dot GA18058 at domone dot kolej dot mff dot cuni dot cz> <20130326172514 dot GA14436 at domone dot kolej dot mff dot cuni dot cz> <5164A07F dot 9090606 at redhat dot com> <20130410062509 dot GA5995 at domone dot kolej dot mff dot cuni dot cz>
On 04/10/2013 02:25 AM, OndÅej BÃlka wrote:
>>> On previous test my implementations gains mostly when current
>>> implementation computed jump is not in cache and this benchmark
>>> underestimates this factor.
>>
>> So a win for one and a loss for the other.
>>
>> How much of a win and how much of a loss?
>>
> When I did profiling it supports theory that cache cost dominates and my
> implementation is faster. Result is here.
>
> http://kam.mff.cuni.cz/~ondra/benchmark_string/memset_profile/result.html
Nice results.
> Results are slower when random test, I am not sure why.
I think we need to answer that before we can move forward.
I don't have any interesting ideas though.
Cheers,
Carlos.