linux-kernel - Re: InfiniBand-ocrdma: Delete unnecessary variable initialisations in 11 functions

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Message-ID: <20160115150935.GA32346@leon.nu>
Date:	Fri, 15 Jan 2016 17:09:35 +0200
From:	Leon Romanovsky <leon@...n.nu>
To:	SF Markus Elfring <elfring@...rs.sourceforge.net>
Cc:	linux-rdma@...r.kernel.org,
	Devesh Sharma <devesh.sharma@...gotech.com>,
	Doug Ledford <dledford@...hat.com>,
	Hal Rosenstock <hal.rosenstock@...il.com>,
	Mitesh Ahuja <mitesh.ahuja@...gotech.com>,
	Sean Hefty <sean.hefty@...el.com>,
	Selvin Xavier <selvin.xavier@...gotech.com>,
	LKML <linux-kernel@...r.kernel.org>,
	kernel-janitors@...r.kernel.org,
	Julia Lawall <julia.lawall@...6.fr>
Subject: Re: InfiniBand-ocrdma: Delete unnecessary variable initialisations
 in 11 functions

On Fri, Jan 15, 2016 at 03:50:27PM +0100, SF Markus Elfring wrote:
> >> The variable "status" will be set to an appropriate value a bit later.
> >> Thus omit the explicit initialisation at the beginning.
> > 
> > What did you try to achieve by this patch?
> 
> I would like to optimise the affected source files a bit.
> Would you like to clarify any measurable effects around the implementation
> detail when various variables will only be initialised immediately
> before they will be read again?

Compiler will drop this variable initialization by itself because
there are no reads between this variable initialization and write.

I recommend you to take a look on the assembly code and ensure it
by yourself.

The proposed change won't affect performance at all.

> 
> Regards,
> Markus