On 03/24/20 16:59, Kinney, Michael D wrote:
> How was the milliseconds units selected?
I suggested msecs for continuity with the pre-patch unit:
#define AP_CHECK_INTERVAL (EFI_TIMER_PERIOD_MILLISECONDS (100))
> We have other PCDs that provide timer intervals in
> 100ns unit and my microseconds. I would prefer we
> be consistent so platform developers do not have
> to keep track of so many different units for time
> intervals.
Sounds OK to me.
What's more: your suggestion points at a bug in the v2 patch. The patch
replaces the argument for the gBS->SetTimer() service's "TriggerTime"
parameter, namely:
Status = gBS->SetTimer (
mCheckAllApsEvent,
TimerPeriodic,
- AP_CHECK_INTERVAL
+ PcdGet64 (PcdCpuApStatusCheckInterval)
);
But that parameter is taken in units of 100ns, per spec.
Pre-patch, AP_CHECK_INTERVAL takes that into account:
#define EFI_TIMER_PERIOD_MILLISECONDS(Milliseconds)
MultU64x32((UINT64)(Milliseconds), 10000)
but post-patch, the PCD does not:
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuApStatusCheckInterval|100|UINT64|0x0000001E
So this patch would shorten the interval by a divisor of 10000 at once, namely
from (100 * 10000) * 100ns, to 100 * 100ns.
The fix is to update the PCD comments according to your remark, and to change
the default PCD value to (100 * 10000) = 1000,000.
Thanks,
Laszlo
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