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Subject: Re: [Qemu-devel] [RFC 05/10] extract TBContext from TCGContext.
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To: Peter Maydell <peter.maydell@linaro.org>, =?UTF-8?B?S09OUkFEIEZyw6lkw6k=?= =?UTF-8?B?cmlj?= <fred.konrad@greensocs.com>
Cc: mttcg@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 01/29/2015 07:44 AM, Peter Maydell wrote:
> 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...)

Seconded.


r~