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From: Paolo Bonzini <pbonzini@redhat.com>
To: Pranith Kumar <bobby.prani@gmail.com>,
	Richard Henderson <rth@twiddle.net>,
	Peter Maydell <peter.maydell@linaro.org>,
	"Emilio G. Cota" <cota@braap.org>
Cc: "Alex Bennée" <alex.bennee@linaro.org>,
	qemu-devel <qemu-devel@nongnu.org>
Subject: Re: [Qemu-devel] GSoC 2017 Proposal: TCG performance enhancements
Date: Mon, 27 Mar 2017 13:32:37 +0200	[thread overview]
Message-ID: <e274d249-806e-473b-2a44-0ce26fd847cb@redhat.com> (raw)
In-Reply-To: <CAJhHMCBwu-pVAyxN+w8SSo19wi3DW3JCRRF-K1Sj9zYqGYkFvQ@mail.gmail.com>



On 25/03/2017 17:52, Pranith Kumar wrote:
> * Implement an LRU translation block code cache.
> 
>   In the current TCG design, when the translation cache fills up, we flush all
>   the translated blocks (TBs) to free up space. We can improve this situation
>   by not flushing the TBs that were recently used i.e., by implementing an LRU
>   policy for freeing the blocks. This should avoid the re-translation overhead
>   for frequently used blocks and improve performance.

IIRC, Emilio measured one flush every roughly 10 seconds with 128 MB
cache in system emulation mode---and "never" is a pretty accurate
estimate for user-mode emulation.  This means that a really hot block
would be retranslated very quickly.

Paolo

  parent reply	other threads:[~2017-03-27 11:32 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-03-25 16:52 [Qemu-devel] GSoC 2017 Proposal: TCG performance enhancements Pranith Kumar
2017-03-27 10:57 ` Richard Henderson
2017-03-27 13:22   ` Alex Bennée
2017-03-28  3:03   ` Pranith Kumar
2017-03-28  3:09     ` Pranith Kumar
2017-03-28 10:03       ` Stefan Hajnoczi
2017-06-02 23:39   ` [Qemu-devel] [PATCH] tcg: allocate TB structs before the corresponding translated code Emilio G. Cota
2017-06-04 17:47     ` Richard Henderson
2017-03-27 11:32 ` Paolo Bonzini [this message]
2017-03-28  3:07   ` [Qemu-devel] GSoC 2017 Proposal: TCG performance enhancements Pranith Kumar
2017-03-27 15:54 ` Stefan Hajnoczi
2017-03-27 17:13   ` Pranith Kumar
2017-06-06 17:13 ` Emilio G. Cota
2017-06-07 10:15   ` Alex Bennée
2017-06-07 11:12   ` Lluís Vilanova
2017-06-07 12:07     ` Peter Maydell
2017-06-07 13:35       ` Paolo Bonzini
2017-06-07 15:52         ` Lluís Vilanova
2017-06-07 16:09           ` Alex Bennée
2017-06-07 17:07           ` Paolo Bonzini
2017-06-07 15:45       ` Lluís Vilanova
2017-06-07 16:17         ` Peter Maydell
2017-06-07 22:49         ` Emilio G. Cota

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