Re: [Qemu-devel] [PATCH] icount: Fix virtual clock start value on ARM

[Paolo Bonzini <pbonzini@redhat.com>]

Il 23/07/2014 11:41, Peter Maydell ha scritto:
> On 23 July 2014 10:11, Sebastian Tanase <sebastian.tanase@openwide.fr> wrote:
>> When using the icount option on ARM, the virtual
>> clock starts counting at realtime clock but it
>> should start at 0.
>> This small fix addresses this issue.
>>
>> Signed-off-by: Sebastian Tanase <sebastian.tanase@openwide.fr>
>> ---
>>  cpus.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/cpus.c b/cpus.c
>> index 5e7f2cf..de18ece 100644
>> --- a/cpus.c
>> +++ b/cpus.c
>> @@ -104,7 +104,7 @@ static bool all_cpu_threads_idle(void)
>>
>>  /* Compensate for varying guest execution speed.  */
>>  static int64_t qemu_icount_bias;
>> -static int64_t vm_clock_warp_start;
>> +static int64_t vm_clock_warp_start = -1;
>>  /* Conversion factor from emulated instructions to virtual clock ticks.  */
>>  static int icount_time_shift;
>>  /* Arbitrarily pick 1MIPS as the minimum allowable speed.  */
> 
> Commit message says this is fixing an ARM bug but this is
> a generic file. Is this actually a bug with wider scope than just
> ARM?

Yes, see the discussion yesterday under "Re: [RFC PATCH V4 6/6] monitor:
Add drift info to 'info jit'" and "Re: [RFC PATCH V4 0/6] icount:
Implement delay algorithm between guest and host clocks".

Paolo