From: Larry Finger <Larry.Finger@lwfinger.net>
To: David Laight <David.Laight@ACULAB.COM>,
ByeoungWook Kim <quddnr145@gmail.com>
Cc: "kvalo@codeaurora.org" <kvalo@codeaurora.org>,
"chaoming_li@realsil.com.cn" <chaoming_li@realsil.com.cn>,
"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] rtlwifi: Fix improve function 'rtl_addr_delay()' in core.c
Date: Thu, 4 Feb 2016 09:43:58 -0600 [thread overview]
Message-ID: <56B371BE.1060805@lwfinger.net> (raw)
In-Reply-To: <063D6719AE5E284EB5DD2968C1650D6D1CCD61C8@AcuExch.aculab.com>
On 02/04/2016 03:48 AM, David Laight wrote:
> From: Larry Finger
>> Sent: 03 February 2016 19:45
> ...
>> The performance will depend on where you satisfy the condition. All switch cases
>> have the same execution time, but in the if .. else if .. else form, the earlier
>> tests execute more quickly. I'm not sure that one can make any blanket statement
>> about performance. Certainly, the switch version will be larger. For a switch
>> with 8 cases plus default, the object code if 43 bytes larger than the nested
>> ifs in a test program that I created. That is a significant penalty.
>
> There is also the penalty of the (likely) data cache miss reading the jump table.
> But given this code is all about generating a variable delay the execution
> speed is probably irrelevant.
>
> It would be much more interesting if the delay could be changed for sleeps.
Unfortunately, sleeping is not possible for the routines that call rtl_addr_delay().
Larry
next prev parent reply other threads:[~2016-02-04 15:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-02-03 1:59 [PATCH 1/2] rtlwifi: Fix improve function 'rtl_addr_delay()' in core.c Byeoungwook Kim
2016-02-03 2:07 ` Julian Calaby
2016-02-03 14:41 ` David Laight
2016-02-03 17:49 ` ByeoungWook Kim
2016-02-03 19:44 ` Larry Finger
2016-02-04 9:48 ` David Laight
2016-02-04 15:43 ` Larry Finger [this message]
2016-02-04 16:02 ` David Laight
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