From: Carsten Langgaard <carstenl@mips.com>
To: "Gleb O. Raiko" <raiko@niisi.msk.ru>
Cc: Ralf Baechle <ralf@oss.sgi.com>,
Jon Burgess <Jon_Burgess@eur.3com.com>,
linux-mips@oss.sgi.com
Subject: Re: mips32_flush_cache routine corrupts CP0_STATUS with gcc-2.96
Date: Thu, 11 Jul 2002 12:46:37 +0200 [thread overview]
Message-ID: <3D2D620D.95E1BF30@mips.com> (raw)
In-Reply-To: 3D2D5FA5.5D964B68@niisi.msk.ru
"Gleb O. Raiko" wrote:
> Carsten Langgaard wrote:
> >
> > "Gleb O. Raiko" wrote:
> > > Basically, requirement of uncached run makes hadrware logic much simpler
> > > and allows to save silicon a bit.
> >
> > That could be true, but then again I suggest making specific cache routines for those
> > CPUs.
> > It would be a real performance hit for the rest of us, if we have to operate from
> > uncached space.
> >
>
> In theory, yes, there is a performance penalty. In practice, I doubt
> this penalty is significant. Sure, Linux likes to flush cahces, not to
> say more. But, did somebody measure the penalty of uncached runs? Even
> with microbencnmarks like lmbench.
Yes, I have tried running linux this way, because I wanted to eliminate the reason I sow
cache problems on one of our tests chip, was due to execute the cache operating
instruction from cached space.
I didn't thought it was that big a penalty, because you are flushing the cache anyway, but
I didn't had to run any benchmarks, so obviously was it when I booted my system.
>
> Regards,
> Gleb.
--
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next prev parent reply other threads:[~2002-07-11 10:43 UTC|newest]
Thread overview: 40+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-07-10 14:16 mips32_flush_cache routine corrupts CP0_STATUS with gcc-2.96 Jon Burgess
2002-07-11 0:15 ` Ralf Baechle
2002-07-11 8:48 ` Gleb O. Raiko
2002-07-11 9:18 ` Carsten Langgaard
2002-07-11 10:06 ` Gleb O. Raiko
2002-07-11 10:15 ` Carsten Langgaard
2002-07-11 10:36 ` Gleb O. Raiko
2002-07-11 10:46 ` Carsten Langgaard [this message]
2002-07-11 11:12 ` Ralf Baechle
2002-07-11 17:01 ` Maciej W. Rozycki
2002-07-11 23:02 ` Dominic Sweetman
2002-07-12 0:24 ` Ralf Baechle
2002-07-12 10:37 ` Gleb O. Raiko
2002-07-12 18:40 ` Maciej W. Rozycki
2002-07-11 11:23 ` Maciej W. Rozycki
2002-07-11 13:11 ` Gleb O. Raiko
2002-07-11 13:41 ` Maciej W. Rozycki
2002-07-11 15:27 ` Gleb O. Raiko
2002-07-11 15:59 ` Maciej W. Rozycki
2002-07-12 10:26 ` Gleb O. Raiko
2002-07-12 19:02 ` Maciej W. Rozycki
2002-07-15 9:16 ` Gleb O. Raiko
2002-07-16 9:00 ` Maciej W. Rozycki
2002-07-16 10:20 ` Gleb O. Raiko
2002-07-16 10:36 ` Maciej W. Rozycki
2002-07-11 7:34 ` Carsten Langgaard
2002-07-11 9:49 Jon Burgess
2002-07-11 12:13 ` Ralf Baechle
2002-07-12 9:18 ` Carsten Langgaard
2002-07-11 12:11 Jon Burgess
2002-07-11 16:53 ` Jun Sun
2002-07-11 16:33 Jon Burgess
2002-07-12 9:08 Sedjai, Mohamed
2002-07-12 9:08 ` Sedjai, Mohamed
2002-07-12 9:26 ` Geert Uytterhoeven
2002-07-12 9:40 ` Carsten Langgaard
2002-07-12 15:24 Jon Burgess
2002-07-15 9:42 Jon Burgess
2002-07-22 8:18 Sedjai, Mohamed
2002-07-22 8:18 ` Sedjai, Mohamed
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