linux-kernel - Re: [PATCH 1/2] lib: Provide generic atomic64

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sun, 14 Jun 2009 14:53:09 +0300
From:	Avi Kivity <avi@...hat.com>
To:	Linus Torvalds <torvalds@...ux-foundation.org>
CC:	Paul Mackerras <paulus@...ba.org>, benh@...nel.crashing.org,
	akpm@...ux-foundation.org, linuxppc-dev@...abs.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] lib: Provide generic atomic64_t implementation

Linus Torvalds wrote:
> On Sat, 13 Jun 2009, Linus Torvalds wrote:
>   
>> On Sat, 13 Jun 2009, Paul Mackerras wrote:
>>     
>>> Linus, Andrew: OK if this goes in via the powerpc tree?
>>>       
>> Ok by me.
>>     
>
> Btw, do 32-bit architectures really necessarily want 64-bit performance 
> counters? 
>
> I realize that 32-bit counters will overflow pretty easily, but I do 
> wonder about the performance impact of doing things like hashed spinlocks 
> for 64-bit counters. Maybe the downsides of 64-bit perf counters on such 
> architectures might outweight the upsides?
>   

An alternative implementation using 64-bit cmpxchg will recover most of 
the costs of hashed spinlocks.  I assume most serious 32-bit 
architectures have them?

-- 
error compiling committee.c: too many arguments to function

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/