From: Leon Romanovsky <leon-2ukJVAZIZ/Y@public.gmane.org>
To: SF Markus Elfring
<elfring-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Devesh Sharma
<devesh.sharma-1wcpHE2jlwO1Z/+hSey0Gg@public.gmane.org>,
Doug Ledford <dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
Hal Rosenstock
<hal.rosenstock-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Mitesh Ahuja
<mitesh.ahuja-1wcpHE2jlwO1Z/+hSey0Gg@public.gmane.org>,
Sean Hefty <sean.hefty-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org>,
Selvin Xavier
<selvin.xavier-1wcpHE2jlwO1Z/+hSey0Gg@public.gmane.org>,
LKML <linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
kernel-janitors-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
Julia Lawall <julia.lawall-L2FTfq7BK8M@public.gmane.org>
Subject: Re: InfiniBand-ocrdma: Delete unnecessary variable initialisations in 11 functions
Date: Fri, 15 Jan 2016 17:09:35 +0200 [thread overview]
Message-ID: <20160115150935.GA32346@leon.nu> (raw)
In-Reply-To: <56990733.7000506-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
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
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next prev parent reply other threads:[~2016-01-15 15:09 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <566ABCD9.1060404@users.sourceforge.net>
2015-12-26 18:39 ` [PATCH 0/6] InfiniBand-ocrdma: Fine-tuning for some function implementations SF Markus Elfring
2015-12-26 18:43 ` [PATCH 1/6] InfiniBand-ocrdma: One variable and jump label less in ocrdma_alloc_ucontext_pd() SF Markus Elfring
2015-12-26 19:41 ` kbuild test robot
2015-12-26 21:28 ` [PATCH v2 1/6] InfiniBand-ocrdma: One " SF Markus Elfring
2016-01-11 13:11 ` Selvin Xavier
2015-12-26 18:50 ` [PATCH 5/6] InfiniBand-ocrdma: Returning only value constants in ocrdma_resize_cq() SF Markus Elfring
2015-12-26 18:51 ` [PATCH 6/6] InfiniBand-ocrdma: Delete an unnecessary variable in ocrdma_dealloc_pd() SF Markus Elfring
[not found] ` <567EDED5.4040201-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
2015-12-26 18:45 ` [PATCH 2/6] InfiniBand-ocrdma: Delete unnecessary variable initialisations in 11 functions SF Markus Elfring
2015-12-26 18:47 ` [PATCH 3/6] InfiniBand-ocrdma: Returning only value constants in ocrdma_qp_state_change() SF Markus Elfring
2015-12-26 18:49 ` [PATCH 4/6] InfiniBand-ocrdma: Return a value from a function call in _ocrdma_modify_qp() directly SF Markus Elfring
2016-01-14 17:18 ` [PATCH v3 0/6] InfiniBand-ocrdma: Fine-tuning for some function implementations SF Markus Elfring
2016-01-14 17:43 ` [PATCH v3 2/6] InfiniBand-ocrdma: Delete unnecessary variable initialisations in 11 functions SF Markus Elfring
2016-01-15 13:20 ` Leon Romanovsky
[not found] ` <20160115132014.GC30615-2ukJVAZIZ/Y@public.gmane.org>
2016-01-15 14:50 ` SF Markus Elfring
[not found] ` <56990733.7000506-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
2016-01-15 15:09 ` Leon Romanovsky [this message]
[not found] ` <20160115150935.GA32346-2ukJVAZIZ/Y@public.gmane.org>
2016-01-15 15:26 ` SF Markus Elfring
[not found] ` <56990FAC.6000506-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
2016-01-15 15:59 ` Leon Romanovsky
[not found] ` <20160115155938.GB32346-2ukJVAZIZ/Y@public.gmane.org>
2016-01-15 16:10 ` Dan Carpenter
2016-01-15 16:24 ` SF Markus Elfring
[not found] ` <56991D52.8030808-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
2016-01-15 17:00 ` Leon Romanovsky
[not found] ` <20160115170048.GC32346-2ukJVAZIZ/Y@public.gmane.org>
2016-01-15 17:19 ` Bart Van Assche
2016-01-15 17:41 ` Leon Romanovsky
2016-01-15 18:19 ` SF Markus Elfring
2016-01-16 6:18 ` Leon Romanovsky
[not found] ` <20160116061843.GE32346-2ukJVAZIZ/Y@public.gmane.org>
2016-01-16 8:30 ` SF Markus Elfring
2016-01-14 17:45 ` [PATCH v3 3/6] InfiniBand-ocrdma: Returning only value constants in ocrdma_qp_state_change() SF Markus Elfring
2016-01-14 17:48 ` [PATCH v3 4/6] InfiniBand-ocrdma: Return a value from a function call in _ocrdma_modify_qp() directly SF Markus Elfring
[not found] ` <5697D865.5010507-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
2016-01-14 17:38 ` [PATCH v3 1/6] InfiniBand-ocrdma: One jump label less in ocrdma_alloc_ucontext_pd() SF Markus Elfring
2016-01-14 17:50 ` [PATCH v3 5/6] InfiniBand-ocrdma: Returning only value constants in ocrdma_resize_cq() SF Markus Elfring
2016-01-14 17:51 ` [PATCH v3 6/6] InfiniBand-ocrdma: Delete an unnecessary variable in ocrdma_dealloc_pd() SF Markus Elfring
2015-12-27 12:36 ` [PATCH 0/2] InfiniBand-iSER: Refactoring for two function implementations SF Markus Elfring
2015-12-27 12:40 ` [PATCH 1/2] InfiniBand-iSER: One jump label less in iser_reg_sig_mr() SF Markus Elfring
2015-12-27 12:41 ` [PATCH 2/2] InfiniBand-iSER-target: One jump label less in isert_reg_sig_mr() SF Markus Elfring
2015-12-27 15:26 ` [PATCH 0/2] InfiniBand-iSER: Refactoring for two function implementations Sagi Grimberg
[not found] ` <567FDB4E.2040000-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
2015-12-27 12:43 ` Leon Romanovsky
2015-12-27 12:52 ` Leon Romanovsky
2016-01-06 18:47 ` Nicholas A. Bellinger
2016-08-20 6:01 ` [PATCH] mlx5/core: Use memdup_user() rather than duplicating its implementation SF Markus Elfring
[not found] ` <ceb39933-438d-920d-f294-ea0ce32fd171-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
2016-08-20 9:32 ` walter harms
2016-08-23 0:05 ` David Miller
2016-08-21 17:39 ` [PATCH 0/2] IB/core: Fine-tuning for ib_is_udata_cleared() SF Markus Elfring
2016-08-21 17:42 ` [PATCH 1/2] IB/core: Use memdup_user() rather than duplicating its implementation SF Markus Elfring
[not found] ` <f7bb3caf-81cd-fba9-afc8-5fac72b8a4b3-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
2016-08-21 17:45 ` [PATCH 2/2] IB/core: Delete an unnecessary initialisation in ib_is_udata_cleared() SF Markus Elfring
2016-08-21 18:03 ` [PATCH 0/2] IB/core: Fine-tuning for ib_is_udata_cleared() Joe Perches
[not found] ` <1471802623.3746.1.camel-6d6DIl74uiNBDgjK7y7TUQ@public.gmane.org>
2016-08-21 19:51 ` SF Markus Elfring
[not found] ` <683187e0-2e6a-88c0-f87a-9c5f0489370a-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org>
2016-08-21 19:53 ` Joe Perches
[not found] ` <1471809188.3746.18.camel-6d6DIl74uiNBDgjK7y7TUQ@public.gmane.org>
2016-08-21 20:15 ` SF Markus Elfring
2016-08-22 9:46 ` Yann Droneaud
[not found] ` <1471859215.2764.24.camel-RlY5vtjFyJ3QT0dZR+AlfA@public.gmane.org>
2016-08-22 16:30 ` [PATCH v2] IB/core: Use memdup_user() rather than duplicating its implementation SF Markus Elfring
2016-08-23 16:43 ` Doug Ledford
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