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From: Chris Snook <csnook@redhat.com>
To: "J.C. Pizarro" <jcpiza@gmail.com>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: Why /proc/cpuinfo doesn't print L1,L2,L3 caches?
Date: Tue, 25 Mar 2008 17:57:58 -0400	[thread overview]
Message-ID: <47E97566.5020003@redhat.com> (raw)
In-Reply-To: <998d0e4a0803251439u4bf09fb1ye568fc1970b0200f@mail.gmail.com>

J.C. Pizarro wrote:
> $ cat /proc/cpuinfo
> processor       : 0
> vendor_id       : AuthenticAMD
> cpu family      : 15
> model           : 47
> model name      : AMD Athlon(tm) 64 Processor 3200+
> ...
> cache size      : 512 KB
> ...
> 
> The cache size is currently misinformed. It's not the real size because
> it's 64+64+512 KiB = 640 KiB, not 512 KB.
> 
> How can i know what hw-caches use the processors?
> The current kernel doesn't know well what hw-caches uses.
> 
> The good proposal is by example (the data below are not real):
> * In old AMD Athlon64:
> 
> cache L1        : 64 KiB I + 64 KiB D, 64 B line, direct way, ...
> cache L2        : 512 KiB I+D-shared, exclusive, 128 associative way, ...
> cache L3        : none
> 
> * In Intel Core Duo:
> processor       : 0
> cache L1        : 32 KiB I + 32 KiB D, 64 B line, direct way, ...
> cache L2        : 2048 KiB Cores-shared, inclusive, 128 associative way, ...
> cache L3        : none
> 
> processor       : 1
> cache L1        : 32 KiB I + 32 KiB D, 64 B line, direct way, ...
> cache L2        : 2048 KiB cores-shared, inclusive, 128 associative way, ...
> cache L3        : none
> 
> * In Quad:
> processor       : 0
> cache L1        : 32 KiB I + 32 KiB D, 64 B line, direct way, ...
> cache L2        : 2048+2048 KiB pair-cores-shared, inclusive, 128
> associative way, ...
> cache L3        : none
> ...
> processor       : 3
> cache L1        : 32 KiB I + 32 KiB D, 64 B line, direct way, ...
> cache L2        : 2048+2048 KiB pair-cores-shared, inclusive, 128
> associative way, ...
> cache L3        : none
> 
> It above is an example, put your symbols to /proc/cpuinfo in a
> convenient manner.
> 
>    Good bye ;)

I think you want this:

/sys/devices/system/cpu/cpu0/cache

/proc/cpuinfo is intended to give a general summary of certain properties of the 
processor that tend to be particularly interesting, and present them all in one 
place.  It is not intended to expose everything the kernel knows about every 
processor on the system.

-- Chris

  reply	other threads:[~2008-03-25 21:58 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-25 21:39 Why /proc/cpuinfo doesn't print L1,L2,L3 caches? J.C. Pizarro
2008-03-25 21:57 ` Chris Snook [this message]
2008-03-25 22:50   ` J.C. Pizarro
2008-03-25 22:59     ` Chris Snook
2008-03-25 23:10       ` J.C. Pizarro
2008-03-25 23:14         ` Chris Snook
2008-03-26  4:29   ` Andrey Borzenkov
2008-03-26  8:54   ` consistency: temperature versus metric bytes (was: Re: Why /proc/cpuinfo doesn't print L1,L2,L3 caches?) Geert Uytterhoeven
2008-03-26  1:39 ` Why /proc/cpuinfo doesn't print L1,L2,L3 caches? Dave Jones

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