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

[Alex Bennée]

Sergey Fedorov <address@hidden> writes:

> On 05/04/16 18:32, Alex Bennée wrote:
>> diff --git a/cpus.c b/cpus.c
>> index 46732a5..8d27fb0 100644
>> --- a/cpus.c
>> +++ b/cpus.c
>
> (snip)
>
>> @@ -146,6 +147,48 @@ typedef struct TimersState {
>>  } TimersState;
>>
>>  static TimersState timers_state;
>> +static bool mttcg_enabled;
>> +
>> +static QemuOptsList qemu_tcg_opts = {
>> +    .name = "tcg",
>> +    .head = QTAILQ_HEAD_INITIALIZER(qemu_tcg_opts.head),
>> +    .desc = {
>> +        {
>> +            .name = "mttcg",
>> +            .type = QEMU_OPT_BOOL,
>> +            .help = "Enable/disable multi-threaded TCG",
>> +        },
>> +        { /* end of list */ }
>> +    },
>> +};
>> +
>> +static void tcg_register_config(void)
>> +{
>> +    qemu_add_opts(&qemu_tcg_opts);
>> +}
>> +
>> +opts_init(tcg_register_config);
>> +
>> +static bool default_mttcg_enabled(void)
>> +{
>> +    /*
>> +     * TODO: Check if we have a chance to have MTTCG working on this 
>> guest/host.
>> +     *       Basically is the atomic instruction implemented? Is there any
>> +     *       memory ordering issue?
>> +     */
>
> I think this could be decided in configure/makefiles.

I was think we might have other interactions, like if the user enabled
replay/playback mode. There is also an argument that by having the logic
in the code it's easier for developers to see the logic as people don't
generally grok Makefiles.

>
>> +    return false;
>> +}
>> +
>> +void qemu_tcg_configure(QemuOpts *opts)
>> +{
>> +    mttcg_enabled = qemu_opt_get_bool(opts, "mttcg", 
>> default_mttcg_enabled());
>> +}
>> +
>> +bool qemu_tcg_mttcg_enabled(void)
>> +{
>> +    return mttcg_enabled;
>> +}
>> +
>>
>>  int64_t cpu_get_icount_raw(void)
>>  {
>> diff --git a/include/qom/cpu.h b/include/qom/cpu.h
>> index 13eeaae..5e3826c 100644
>> --- a/include/qom/cpu.h
>> +++ b/include/qom/cpu.h
>> @@ -369,6 +369,20 @@ extern struct CPUTailQ cpus;
>>  extern __thread CPUState *current_cpu;
>>
>>  /**
>> + * qemu_tcg_enable_mttcg:
>> + * Enable the MultiThread TCG support.
>> + */
>> +void qemu_tcg_enable_mttcg(void);
>
> Seems to be an orphaned declaration.
>
> Kind regards,
> Sergey


--
Alex Bennée