linux-kernel - RE: [PATCH RFC] [x86] Optimize copy-page by reducing impact from HW prefetch

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 for Android: free password hash cracker in your pocket

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

Message-ID: <C10D3FB0CD45994C8A51FEC1227CE22F27050B5318@shsmsx502.ccr.corp.intel.com>
Date:	Tue, 28 Jun 2011 23:23:52 +0800
From:	"Ma, Ling" <ling.ma@...el.com>
To:	Ingo Molnar <mingo@...e.hu>, Andi Kleen <andi@...stfloor.org>
CC:	"hpa@...or.com" <hpa@...or.com>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH RFC] [x86] Optimize copy-page by reducing impact from HW
 prefetch

Hi Ingo
 
> Ling, mind double checking which one is the faster/better one on SNB,
> in cold-cache and hot-cache situations, copy_page or copy_page_c?
Copy_page_c 
on hot-cache copy_page_c on SNB combines data to 128bit (processor limit 128bit/cycle for write) after startup latency
so it is faster than copy_page which provides 64bit/cycle for write.

on cold-cache copy_page_c doesn't use prefetch, which uses prfetch according to copy size,
so copy_page function is better. 

Thanks
Ling

--
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/