From: Marcelo Tosatti <marcelo.tosatti@cyclades•com>
To: Dan Malek <dan@embeddededge•com>
Cc: Joakim Tjernlund <joakim.tjernlund@lumentis•se>,
linux-ppc-embedded <linuxppc-embedded@ozlabs•org>
Subject: Re: How to fix 8xx dcbst bug?
Date: Sat, 7 May 2005 18:47:39 -0300 [thread overview]
Message-ID: <20050507214739.GF16996@logos.cnet> (raw)
In-Reply-To: <52dc3ae70f883699b1e48b7d742afcaf@embeddededge.com>
On Sat, May 07, 2005 at 09:10:17PM -0400, Dan Malek wrote:
>
> On May 6, 2005, at 11:45 AM, Marcelo Tosatti wrote:
>
> >
> >Hi Dan,
> >
> >So, restarting this conversation...
>
> One of the things I don't want to lose sight of during
> all of this is the real performance problem in 2.6.
> Your test results show there is something that needs
> attention, regardless of using pinned entries. We
> need to continue some of this investigation, it
> affects all processors.
True.
Follows some useful data:
"itlb-content-before" and "itlb-content-after" are dumps of TLB cache
content before and after "sys_read()", for both v2.4 and v2.6.
The "diff" output shows which TLB's have been faulted in:
[marcelo@logos itlb]$ diff -u 24-itlb-content-before.txt 24-itlb-content-after.txt
| grep SPR | grep 816 | grep "+"
+SPR 816 : 0x0ffe800f 268337167
+SPR 816 : 0x0ffeb00f 268349455
+SPR 816 : 0xc009e01f -1073094625
+SPR 816 : 0xc009d01f -1073098721
+SPR 816 : 0xc000301f -1073729505
+SPR 816 : 0xc009c01f -1073102817
[marcelo@logos itlb]$ diff -u 24-itlb-content-before.txt 24-itlb-content-after.txt
| grep SPR | grep 818 | grep "+" | wc -l
6
Now v2.6:
[marcelo@logos itlb]$ diff -u 26-itlb-before.txt 26-itlb-after.txt
| grep 816 | grep SPR | grep "+"
+SPR 816 : 0x0feda16f 267231599
+SPR 816 : 0xc004b17f -1073434241
+SPR 816 : 0xc004a17f -1073438337
+SPR 816 : 0x0ff7e16f 267903343
+SPR 816 : 0x1001016f 268501359
+SPR 816 : 0xc000217f -1073733249
+SPR 816 : 0xc001617f -1073651329
+SPR 816 : 0xc002e17f -1073553025
+SPR 816 : 0xc010e17f -1072635521
+SPR 816 : 0xc002d17f -1073557121
+SPR 816 : 0xc010d17f -1072639617
+SPR 816 : 0xc000c17f -1073692289
+SPR 816 : 0xc000317f -1073729153
[marcelo@logos itlb]$ diff -u 26-itlb-before.txt 26-itlb-after.txt
| grep 816 | grep SPR | grep "+" | wc -l
13
So, for sys_read() v2.6 i-cache translation footprint is about 100%
more than v2.4.
I suspect that actual cache footprint is higher, too.
next prev parent reply other threads:[~2005-05-09 18:52 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2005-05-06 15:45 How to fix 8xx dcbst bug? Marcelo Tosatti
2005-05-07 18:24 ` Joakim Tjernlund
2005-05-07 13:57 ` Marcelo Tosatti
2005-05-07 18:39 ` Wolfgang Denk
2005-05-07 22:47 ` Joakim Tjernlund
2005-05-08 1:00 ` Dan Malek
2005-05-08 1:10 ` Dan Malek
2005-05-07 21:47 ` Marcelo Tosatti [this message]
2005-05-09 19:25 ` Dan Malek
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