Re: [Qemu-devel] [RFC v2 08/11] tcg: add options for enabling MTTCG

["Alex Bennée" <alex.bennee@linaro.org>]

Sergey Fedorov <serge.fdrv@gmail.com> writes:

> On 05/04/16 18:32, Alex Bennée wrote:
>> diff --git a/qemu-options.hx b/qemu-options.hx
>> index a770086..4eca704 100644
>> --- a/qemu-options.hx
>> +++ b/qemu-options.hx
>> @@ -3224,6 +3224,20 @@ Attach to existing xen domain.
>>  xend will use this when starting QEMU (XEN only).
>>  ETEXI
>>
>> +DEF("tcg", HAS_ARG, QEMU_OPTION_tcg, \
>> +    "-tcg [mttcg=on|off] control TCG options\n", QEMU_ARCH_ALL)
>> +STEXI
>> +@item -tcg
>> +@findex -tcg
>> +@table @option
>> +@item mttcg=[on|off]
>> +Control multi-threaded TCG. By default QEMU will enable multi-threaded
>> +emulation for front/back-end combinations that are known to work. The
>> +user may enable it against the defaults however odd guest behaviour
>> +may occur.
>> +@end table
>> +ETEXI
>
> Maybe we'd better use existing qemu accelerator framework and introduce
> "-machine accel=mttcg" option?

My worry would be breaking existing code which assumes kvm | tcg. We
will want to enable mttcg by default for combos that work without having
to tweak tooling that already uses the -machine options.

--
Alex Bennée