Re: [Patch] UefiCpuPkg/MpInitLib: Keep compatible with former solution.

["Dong, Eric" <eric.dong@intel.com>]

Laszlo,

Update both and pushed the change at 86121874.

Thanks,
Eric

> -----Original Message-----
> From: edk2-devel [mailto:edk2-devel-bounces@lists.01.org] On Behalf Of
> Laszlo Ersek
> Sent: Thursday, October 26, 2017 4:26 PM
> To: Dong, Eric <eric.dong@intel.com>; edk2-devel@lists.01.org
> Cc: Ni, Ruiyu <ruiyu.ni@intel.com>
> Subject: Re: [edk2] [Patch] UefiCpuPkg/MpInitLib: Keep compatible with
> former solution.
> 
> On 10/26/17 07:59, Eric Dong wrote:
> > For some special platforms (such as Ovmf), it is possible that, some
> > APs start up *and finish* before the remaining APs not start up *at
> > all*. In this case, the enhance
> 
> (1) I think the word "not" should be removed from the above line, so that we
> get: "some APs start up *and finish* before the remaining APs [] start up *at
> all*".
> 
> (2) For the subject line: can we add "AP counting" or "AP collection"
> somehow? For example:
> 
> UefiCpuPkg/MpInitLib: Keep compatible with former AP counting solution.
> 
> 
> I don't insist, but I think these changes would improve the commit message.
> They can be implemented before pushing. Either way,
> 
> Reviewed-by: Laszlo Ersek <lersek@redhat.com>
> 
> Thank you for the quick update, Eric and Jeff!
> Laszlo
> 
> > solution by changes 0594ec41 not works as expected.
> >
> > This change remove check CpuMpData->CpuCount logic to let old solution
> > still workable if platform owner still set a long time for
> > PcdCpuApInitTimeOutInMicroSeconds. It's platform owner's response to
> > decide which solution to use.
> >
> > Cc: Ruiyu Ni <ruiyu.ni@intel.com>
> > Cc: Laszlo Ersek <lersek@redhat.com>
> > Cc: Jeff Fan <vanjeff_919@hotmail.com>
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Eric Dong <eric.dong@intel.com>
> > ---
> >  UefiCpuPkg/Library/MpInitLib/MpLib.c | 21 +++++++++++++--------
> >  1 file changed, 13 insertions(+), 8 deletions(-)
> >
> > diff --git a/UefiCpuPkg/Library/MpInitLib/MpLib.c
> > b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> > index 48f930b..18060fd 100644
> > --- a/UefiCpuPkg/Library/MpInitLib/MpLib.c
> > +++ b/UefiCpuPkg/Library/MpInitLib/MpLib.c
> > @@ -936,15 +936,20 @@ WakeUpAP (
> >      }
> >      if (CpuMpData->InitFlag == ApInitConfig) {
> >        //
> > -      // Wait for one potential AP waken up in one specified period
> > +      // Here support two methods to collect AP count through adjust
> > +      // PcdCpuApInitTimeOutInMicroSeconds values.
> >        //
> > -      if (CpuMpData->CpuCount == 0) {
> > -        TimedWaitForApFinish (
> > -          CpuMpData,
> > -          PcdGet32 (PcdCpuMaxLogicalProcessorNumber) - 1,
> > -          PcdGet32 (PcdCpuApInitTimeOutInMicroSeconds)
> > -          );
> > -      }
> > +      // one way is set a value to just let the first AP to start the
> > +      // initialization, then through the later while loop to wait all Aps
> > +      // finsh the initialization.
> > +      // The other way is set a value to let all APs finished the initialzation.
> > +      // In this case, the later while loop is useless.
> > +      //
> > +      TimedWaitForApFinish (
> > +        CpuMpData,
> > +        PcdGet32 (PcdCpuMaxLogicalProcessorNumber) - 1,
> > +        PcdGet32 (PcdCpuApInitTimeOutInMicroSeconds)
> > +        );
> >
> >        while (CpuMpData->MpCpuExchangeInfo->NumApsExecuting != 0) {
> >          CpuPause();
> >
> 
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