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From: Peter Maydell <peter.maydell@linaro.org>
Date: Thu, 29 Jan 2015 15:44:53 +0000
Message-ID: <CAFEAcA8cZD1REWcvJJVv6AjB95GXgA3FueQ8b6ZSaCj8JTnGAg@mail.gmail.com>
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Subject: Re: [Qemu-devel] [RFC 05/10] extract TBContext from TCGContext.
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To: =?UTF-8?B?S09OUkFEIEZyw6lkw6lyaWM=?= <fred.konrad@greensocs.com>
Cc: mttcg@listserver.greensocs.com, "J. Kiszka" <jan.kiszka@siemens.com>, Mark Burton <mark.burton@greensocs.com>, QEMU Developers <qemu-devel@nongnu.org>, Alexander Graf <agraf@suse.de>, Paolo Bonzini <pbonzini@redhat.com>

On 16 January 2015 at 17:19,  <fred.konrad@greensocs.com> wrote:
> From: KONRAD Frederic <fred.konrad@greensocs.com>
>
> In order to have one TCGContext per thread and a single TBContext we have to
> extract TBContext from TCGContext.

This seems a bit odd. It's not clear to me what the advantages
are of having one TCGContext per thread but only a single
TBContext (as opposed to either (1) having a single TCGContext
and TBContext with locks protecting against multiple threads
generating code at once, or (2) having each thread have its
own TCGContext and TBContext and completely independent codegen).

Maybe it would help if you sketched out your design in a little
more detail in the cover letter, with emphasis on which data
structures are going to be per-thread and which are going to
be shared (and if so how shared).

(Long term we would want to be able to have multiple
TBContexts to support heterogenous systems where CPUs
might be different architectures or have different views
of physical memory...)

thanks
-- PMM