lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
Open Source and information security mailing list archives
| ||
|
Date: Thu, 4 Feb 2016 09:43:58 -0600 From: Larry Finger <Larry.Finger@...inger.net> To: David Laight <David.Laight@...LAB.COM>, ByeoungWook Kim <quddnr145@...il.com> Cc: "kvalo@...eaurora.org" <kvalo@...eaurora.org>, "chaoming_li@...lsil.com.cn" <chaoming_li@...lsil.com.cn>, "linux-wireless@...r.kernel.org" <linux-wireless@...r.kernel.org>, "netdev@...r.kernel.org" <netdev@...r.kernel.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org> Subject: Re: [PATCH 1/2] rtlwifi: Fix improve function 'rtl_addr_delay()' in core.c 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
Powered by blists - more mailing lists