linux-kernel - Re: [RFC PATCH] perf: Add load latency monitoring on Intel Nehalem/Westmere

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:	Thu, 23 Dec 2010 11:18:18 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Lin Ming <ming.m.lin@...el.com>
Cc:	Stephane Eranian <eranian@...gle.com>, Ingo Molnar <mingo@...e.hu>,
	Andi Kleen <andi@...stfloor.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Arjan van de Ven <arjan@...radead.org>,
	lkml <linux-kernel@...r.kernel.org>, paulus <paulus@...ba.org>
Subject: Re: [RFC PATCH] perf: Add load latency monitoring on Intel
 Nehalem/Westmere

On Thu, 2010-12-23 at 16:59 +0800, Lin Ming wrote:
> > {L1, L2, L3, RAM}x{snoop, local, remote}x{shared, exclusive} + {unknown,
> > uncached, IO}
> > 
> > Which takes all of 5 bits to encode.
> 
> Do you mean below encoding?
> 
> bits4 3 2 1 0
>     + + + + +
>     | | | | |
>     | | | {L1, L2, L3, RAM} or {unknown, uncached, IO}
>     | | |
>     | {snoop, local, remote, OTHER}
>     |
>     {shared, exclusive}
> 
> If bits(2-3) is OTHER, then bits(0-1) is the encoding of {unknown,
> uncached, IO}. 

That is most certainly a very valid encoding, and a rather nice one at
that. I hadn't really gone further than: 4*3*2 + 3 < 2^5 :-)

If you also make OTHER=0, then a valid encoding for unknown is also 0,
which is a nice meaning for 0...
--
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/