linux-kernel - Re: [PATCH RFC] [X86] Compile Option Os versus O2 on latest x86 platform

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]

Message-ID: <4B17D3D3.1060502@zytor.com>
Date:	Thu, 03 Dec 2009 07:05:55 -0800
From:	"H. Peter Anvin" <hpa@...or.com>
To:	"Ma, Ling" <ling.ma@...el.com>
CC:	Arjan van de Ven <arjan@...radead.org>,
	Ingo Molnar <mingo@...e.hu>, Dave Jones <davej@...hat.com>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH RFC] [X86] Compile Option Os versus O2 on latest x86 platform

On 12/03/2009 07:03 AM, Ma, Ling wrote:
>> a key question is.. how much more memory do you have free due to -Os?
>> (because memory is cache is performance on a system level as well)
> The kernel code size from Os is 12M, that from O2 is 14M.
>> and how much less icache pressure is there?
> From perf stat report, cache reference(unified cache) from O2 is almost the same with Os.

The icache pressure was substantially higher (by ~10%) in the reports
that I saw.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

--
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/