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From: mitchalsup@aol.com (MitchAlsup1)
Newsgroups: comp.arch
Subject: Re: Privilege Levels Below User
Date: Tue, 11 Jun 2024 21:20:45 +0000
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John Savard wrote:

> On Tue, 11 Jun 2024 08:54:16 +0300, Niklas Holsti
> <niklas.holsti@tidorum.invalid> wrote:

>>Not always. If the mistakenly speculated cache-fetch /evicted/ some 
>>other data from the (finite-sized) cache, and the evicted data are 
>>needed later on the /true/ execution path, the mistakenly speculated 
>>fetch has a /negative/ effect on performance. (This kind of "timing 
>>anomaly" is very bothersome in static WCET analysis.)

That is why you don't update the cache until the causing instruction 
retires.

> Ouch. Another argument for having a victim cache. And a benefit of
> doing it in what is apparently Mitch Alsup's way - holding off cache
> updates until instruction retirement.

Change your thought from victim cache to pipeline buffer pre cache.

> John Savard