Re: [RFC v1 0/2] tcg-cpus: split into 3 tcg variants

[Claudio Fontana]

On 10/14/20 12:14 PM, Alex Bennée wrote:
> 
> Claudio Fontana <cfontana@suse.de> writes:
> 
>> The purpose of this series is to split the tcg-cpus into
>> 3 variants:
>>
>> tcg_cpus_mttcg    (multithreaded tcg vcpus)
>> tcg_cpus_rr       (single threaded round robin vcpus)
>> tcg_cpus_icount   (same as RR, but using icount)
> 
> I've no objection to the cosmetic clean-up but I assume the 3 modes will
> still be available in TCG enabled binaries.

Hi Alex,

yes, all three will be available in the code when enabling TCG.

> 
>>
>> Alex, I read the comment in tcg_start_vcpu_thread saying:
>>
>>     /*
>>      * Initialize TCG regions--once. Now is a good time, because:
>>      * (1) TCG's init context, prologue and target globals have been set up.
>>      * (2) qemu_tcg_mttcg_enabled() works now (TCG init code runs before the
>>      *     -accel flag is processed, so the check doesn't work then).
>>      */
>>
>> Is this actually current?
> 
> Hmm probably not. Now everything is tied to the order of class
> initialisation and realisation. AIUI all properties set by the command
> line should be complete by the time an object realizes and parent
> classes should be processed before their children.

This is great news, as it allows more refactoring as showed on patch 2,

thanks a lot!

Ciao,

Claudio

> 
>>
>> I tried to refactor this (see patch 2), and it seems to work to do
>> the init of regions in tcg_init, and it seems that mttcg_enabled is known
>> already at that point..
>>
>> Ciao,
>>
>> Claudio
>>
>> Claudio Fontana (2):
>>   accel/tcg: split CpusAccel into three TCG variants
>>   accel/tcg: split tcg_start_vcpu_thread
>>
>>  accel/tcg/meson.build       |   9 +-
>>  accel/tcg/tcg-all.c         |  13 +-
>>  accel/tcg/tcg-cpus-icount.c | 145 +++++++++++
>>  accel/tcg/tcg-cpus-icount.h |  20 ++
>>  accel/tcg/tcg-cpus-mttcg.c  | 142 ++++++++++
>>  accel/tcg/tcg-cpus-mttcg.h  |  25 ++
>>  accel/tcg/tcg-cpus-rr.c     | 305 ++++++++++++++++++++++
>>  accel/tcg/tcg-cpus-rr.h     |  26 ++
>>  accel/tcg/tcg-cpus.c        | 500 +-----------------------------------
>>  accel/tcg/tcg-cpus.h        |   9 +-
>>  softmmu/icount.c            |   2 +-
>>  11 files changed, 697 insertions(+), 499 deletions(-)
>>  create mode 100644 accel/tcg/tcg-cpus-icount.c
>>  create mode 100644 accel/tcg/tcg-cpus-icount.h
>>  create mode 100644 accel/tcg/tcg-cpus-mttcg.c
>>  create mode 100644 accel/tcg/tcg-cpus-mttcg.h
>>  create mode 100644 accel/tcg/tcg-cpus-rr.c
>>  create mode 100644 accel/tcg/tcg-cpus-rr.h
> 
>