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Message-ID: <9623c9a50808050031r50db32fcl693bf494890a3940@mail.gmail.com>
Date: Tue, 5 Aug 2008 15:31:44 +0800
From: "Xiao-Feng Li" <xiaofeng.li@gmail.com>
To: dev@harmony.apache.org
Subject: Re: patch for HARMONY-5901 is ready
In-Reply-To: <4bebff790808050011n7b7f5906x6bb563ec19770c11@mail.gmail.com>
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References: <255079590808042103r39efdb66g8f79eeb9d6045888@mail.gmail.com>
	 <4bebff790808050011n7b7f5906x6bb563ec19770c11@mail.gmail.com>

There are more situations that strength reduction can be applicable.
Do we want to make the optimization a general solution or just keep it
case by case?

Thanks,
xiaofeng

On Tue, Aug 5, 2008 at 3:11 PM, Aleksey Shipilev
<aleksey.shipilev@gmail.com> wrote:
> On Tue, Aug 5, 2008 at 8:03 AM, xiaoming gu <xiaoming.gu@gmail.com> wrote:
>> Hi, guys. The patch for harmony-5901 is ready.
> At last! Thanks, Xioaming!
>
>> I compared the performance for all the 5 benchmarks in "Java vs. C
>> benchmark" by Stefan Krause on my desktop
>> workstation (Intel Core 2 Quad Q9550@2.83GHz, 3.23G RAM, Windows XP SP2).
>> With MUL/DIV replaced by shift,
>> spectralnorm is improved more than 29% (from 450258 msec to 319578 msec)
> Can you spend some time and measure how much boost there is, in case
> your _manual_ change of MUL/DIV operations to shifts? I had measured
> +60% boost, so it would be great to conclude whether yours +30% is
> connected with patch overheads (handling negative operands, I guess)
> or your environment.
>
> Thanks,
> Aleksey.
>


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