Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
On 01/10/19 05:51, Ni, Ray wrote:
>
>
>> -Original Message-
>> From: Laszlo Ersek
>> Sent: Wednesday, January 9, 2019 6:35 PM
>> To: Dong, Eric
>> Cc: Brian J. Johnson ; Yao, Jiewen
>> ; Ni, Ray ; edk2-
>> de...@lists.01.org; Kinney, Michael D
>> Subject: Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
>> AP calls PeiService.
>>
>> Hi Eric,
>>
>> On 01/09/19 06:26, Dong, Eric wrote:
>>> Hi all,
>>>
>>> We got some feedback about this BZ. Someone think this timeout is
>> valuable for the debug purpose, and oppose to remove it.
>>> https://bugzilla.tianocore.org/show_bug.cgi?id=1419
>>>
>>> So I'm back to here and want to still use this change. I not use "update
>> PcdSpinLockTimeout to 0 in platform" solution because I think core driver
>> depends on platform policy is not a good design.
>>>
>>> Do you guys have any other concern?
>>
>> sorry, I don't understand.
>>
>> (1) In <https://bugzilla.tianocore.org/show_bug.cgi?id=1419>, where
>> currently comment #2 is the last comment, I don't see any request for
>> keeping the timeout facility.
>
> The comment "timeout is valuable for debugging" is raised in bug scrub
> meeting.
> (Sorry that's not a public meeting yet. I think there is effort to make it
> public, not sure).
>
>>
>> (2) On the mailing list as well, you seem to have received comments only in
>> favor of removing the timeout facility.
>>
>> "Someone think this timeout is valuable for the debug purpose" doesn't cut
>> it, for open development. I don't care about the identity of the person that
>> wants to preserve the feature, but I certainly care about their use case. You
>> shouldn't have to mediate and describe their use case for them, on the list;
>> that's always a lossy process.
>
> Use case of the timeout:
> When someone mis-uses the spin lock that causes dead lock, timeout assertion
> debug message can help the one to know something wrong happens.
> Instead of the system just hangs without any debug message.
>
> But I doubt whether the benefit of timeout is bigger than the potential issue
> it
> brings. Potential issues are:
> 1. User may mis-use time lib in AP procedure causing assertion.
> 2. Not sure HPE Brian's issue is similar to #1. @Brian
>
> Basically, I also don' t like the idea that a BASE Synchronization library
> depends on
> a non-BASE timer lib. It makes the Synchronization library a non-BASE lib in
> most
> of the case. Or platform developer needs some change to make it BASE. Changes
> could be:
> 1. Setting the timeout PCD to 0
> 2. Link to a NULL timer lib.
>
> But for the purpose of avoiding AP calls PeiService, I agree with Eric's
> change.
> I don't think the timer lib dependency blocks Eric's change.
> Agree?
Yes, I do. Replacing the AcquireSpinLock() call with a looped
AcquireSpinLockOrFail() call amounts to acquiring the spinlock, but
without depending on the timeout PCD or on the TimerLib class.
Thanks,
Laszlo
>> Regarding the PCD: I think zeroing "PcdSpinLockTimeout" to disable the
>> timeout case is a valid approach, it's just that we should change the default
>> value in the DEC file to zero. Then the PCD setting will become a burden only
>> for those platforms and those use cases that want to use the timeout
>> feature (such as for debugging).
>>
>> In general, PCD default values in DEC files have to be considered carefully,
>> but in some cases, such changes are the right thing. Another example was
>> 509f8425b75d ("UefiCpuPkg: change PcdCpuSmmStackGuard default to
>> TRUE", 2016-06-06).
>>
>> (You made the same point at the end of
>> <https://bugzilla.tianocore.org/show_bug.cgi?id=1419#c2>.)
>>
>>
>> In addition to changing the default value to zero, I'd suggest moving
>> "PcdSpinLockTimeout" from section
>>
>> [PcdsFixedAtBuild,PcdsPatchableInModule]
>>
>> to section
>>
>> [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
>>
>> so that platforms can enable the "debug" feature (i.e. set a nonzero
>> value) more flexibly.
>>
>> Thanks
>> Laszlo
>>
>>>> -Original Message-
>>>> From: Brian J. Johnson [mailto:brian.john...@hpe.com]
>>>> Sent: Friday, December 21, 2018 12:36 AM
>>>> To: Yao, Jiewen ; Ni, Ruiyu
>>>> ; Dong, Eric ;
>>>> edk2-d
Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
Hi Laszlo,
> -Original Message-
> From: Laszlo Ersek [mailto:ler...@redhat.com]
> Sent: Wednesday, January 9, 2019 6:35 PM
> To: Dong, Eric
> Cc: Brian J. Johnson ; Yao, Jiewen
> ; Ni, Ray ; edk2-
> de...@lists.01.org; Kinney, Michael D
> Subject: Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> AP calls PeiService.
>
> Hi Eric,
>
> On 01/09/19 06:26, Dong, Eric wrote:
> > Hi all,
> >
> > We got some feedback about this BZ. Someone think this timeout is
> valuable for the debug purpose, and oppose to remove it.
> > https://bugzilla.tianocore.org/show_bug.cgi?id=1419
> >
> > So I'm back to here and want to still use this change. I not use "update
> PcdSpinLockTimeout to 0 in platform" solution because I think core driver
> depends on platform policy is not a good design.
> >
> > Do you guys have any other concern?
>
> sorry, I don't understand.
>
> (1) In <https://bugzilla.tianocore.org/show_bug.cgi?id=1419>, where
> currently comment #2 is the last comment, I don't see any request for
> keeping the timeout facility.
Please check Ray's comments I discussed with him offline.
>
> (2) On the mailing list as well, you seem to have received comments only in
> favor of removing the timeout facility.
>
> "Someone think this timeout is valuable for the debug purpose" doesn't cut
> it, for open development. I don't care about the identity of the person that
> wants to preserve the feature, but I certainly care about their use case. You
> shouldn't have to mediate and describe their use case for them, on the list;
> that's always a lossy process.
>
Please check Ray's comments I discussed with him offline.
> Regarding the PCD: I think zeroing "PcdSpinLockTimeout" to disable the
> timeout case is a valid approach, it's just that we should change the default
> value in the DEC file to zero. Then the PCD setting will become a burden only
> for those platforms and those use cases that want to use the timeout
> feature (such as for debugging).
>
> In general, PCD default values in DEC files have to be considered carefully,
> but in some cases, such changes are the right thing. Another example was
> 509f8425b75d ("UefiCpuPkg: change PcdCpuSmmStackGuard default to
> TRUE", 2016-06-06).
>
> (You made the same point at the end of
> <https://bugzilla.tianocore.org/show_bug.cgi?id=1419#c2>.)
>
>
> In addition to changing the default value to zero, I'd suggest moving
> "PcdSpinLockTimeout" from section
>
> [PcdsFixedAtBuild,PcdsPatchableInModule]
>
> to section
>
> [PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
>
> so that platforms can enable the "debug" feature (i.e. set a nonzero
> value) more flexibly.
Agree to do both changes, will submit BZ for it if we get the agreement in
this mailing list.
Thanks,
Eric
>
> Thanks
> Laszlo
>
> >> -Original Message-
> >> From: Brian J. Johnson [mailto:brian.john...@hpe.com]
> >> Sent: Friday, December 21, 2018 12:36 AM
> >> To: Yao, Jiewen ; Ni, Ruiyu
> >> ; Dong, Eric ;
> >> edk2-devel@lists.01.org
> >> Cc: Laszlo Ersek
> >> Subject: Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >> Avoid AP calls PeiService.
> >>
> >> Agreed. We've seen issues on real platforms with timed-out spinlocks
> >> in DXE causing calls to GetPerformanceCounter and DebugAssert. (DXE
> >> has the same code, with the same issues.)
> >>
> >> Note that it's possible to set PcdSpinLockTimeout=0 to work around
> >> the issue on a particular platform, or in a particular module. But
> >> if you have to do that for every module which uses APs, and hence
> >> could contend for a spinlock, it kind of defeats the point We're
> >> better
> off removing the timeout code.
> >>
> >> Thanks,
> >> Brian
> >>
> >> On 12/19/18 8:08 PM, Yao, Jiewen wrote:
> >>> Yes, I agree, if we don't have any real case.
> >>>
> >>>
> >>>> -Original Message-
> >>>> From: Ni, Ruiyu
> >>>> Sent: Thursday, December 20, 2018 10:07 AM
> >>>> To: Dong, Eric ; Yao, Jiewen
> >>>> ; edk2-devel@lists.01.org
> >>>> Cc: Laszlo Ersek
> >>>> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >>>> Avoid AP calls PeiService.
> >>>>
> >>>> Can you just change
Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
Hi Eric,
On 01/09/19 06:26, Dong, Eric wrote:
> Hi all,
>
> We got some feedback about this BZ. Someone think this timeout is valuable
> for the debug purpose, and oppose to remove it.
> https://bugzilla.tianocore.org/show_bug.cgi?id=1419
>
> So I'm back to here and want to still use this change. I not use "update
> PcdSpinLockTimeout to 0 in platform" solution because I think core driver
> depends on platform policy is not a good design.
>
> Do you guys have any other concern?
sorry, I don't understand.
(1) In <https://bugzilla.tianocore.org/show_bug.cgi?id=1419>, where
currently comment #2 is the last comment, I don't see any request for
keeping the timeout facility.
(2) On the mailing list as well, you seem to have received comments only
in favor of removing the timeout facility.
"Someone think this timeout is valuable for the debug purpose" doesn't
cut it, for open development. I don't care about the identity of the
person that wants to preserve the feature, but I certainly care about
their use case. You shouldn't have to mediate and describe their use
case for them, on the list; that's always a lossy process.
Regarding the PCD: I think zeroing "PcdSpinLockTimeout" to disable the
timeout case is a valid approach, it's just that we should change the
default value in the DEC file to zero. Then the PCD setting will become
a burden only for those platforms and those use cases that want to use
the timeout feature (such as for debugging).
In general, PCD default values in DEC files have to be considered
carefully, but in some cases, such changes are the right thing. Another
example was 509f8425b75d ("UefiCpuPkg: change PcdCpuSmmStackGuard
default to TRUE", 2016-06-06).
(You made the same point at the end of
<https://bugzilla.tianocore.org/show_bug.cgi?id=1419#c2>.)
In addition to changing the default value to zero, I'd suggest moving
"PcdSpinLockTimeout" from section
[PcdsFixedAtBuild,PcdsPatchableInModule]
to section
[PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
so that platforms can enable the "debug" feature (i.e. set a nonzero
value) more flexibly.
Thanks
Laszlo
>> -Original Message-
>> From: Brian J. Johnson [mailto:brian.john...@hpe.com]
>> Sent: Friday, December 21, 2018 12:36 AM
>> To: Yao, Jiewen ; Ni, Ruiyu ;
>> Dong, Eric ; edk2-devel@lists.01.org
>> Cc: Laszlo Ersek
>> Subject: Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
>> AP calls PeiService.
>>
>> Agreed. We've seen issues on real platforms with timed-out spinlocks in DXE
>> causing calls to GetPerformanceCounter and DebugAssert. (DXE has the
>> same code, with the same issues.)
>>
>> Note that it's possible to set PcdSpinLockTimeout=0 to work around the issue
>> on a particular platform, or in a particular module. But if you have to do
>> that
>> for every module which uses APs, and hence could contend for a spinlock, it
>> kind of defeats the point We're better off removing the timeout code.
>>
>> Thanks,
>> Brian
>>
>> On 12/19/18 8:08 PM, Yao, Jiewen wrote:
>>> Yes, I agree, if we don't have any real case.
>>>
>>>
>>>> -Original Message-
>>>> From: Ni, Ruiyu
>>>> Sent: Thursday, December 20, 2018 10:07 AM
>>>> To: Dong, Eric ; Yao, Jiewen
>>>> ; edk2-devel@lists.01.org
>>>> Cc: Laszlo Ersek
>>>> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
>>>> Avoid AP calls PeiService.
>>>>
>>>> Can you just change the AcquireSpinLock() behavior to remove the
>>>> Timeout PCD consumption?
>>>>
>>>> I haven't seen a real case that the timed acquisition of spin lock is
>>>> needed.
>>>>
>>>>
>>>> Thanks/Ray
>>>>
>>>>> -Original Message-
>>>>> From: Dong, Eric
>>>>> Sent: Thursday, December 20, 2018 9:23 AM
>>>>> To: Yao, Jiewen ; edk2-devel@lists.01.org
>>>>> Cc: Ni, Ruiyu ; Laszlo Ersek
>>>>> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
>>>>> Avoid AP calls PeiService.
>>>>>
>>>>>
>>>>> Agreed, Maybe it's time to add a new API like
>>>>> AcquireSpinLockWithoutTimeOut?
>>>>>
>>>>> Thanks,
>>>>> Eric
>>>>>> -Original Message-
>>>>>> From: Yao, Jiewen
>>>>>> Sent: Thurs
Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
Hi all,
We got some feedback about this BZ. Someone think this timeout is valuable for
the debug purpose, and oppose to remove it.
https://bugzilla.tianocore.org/show_bug.cgi?id=1419
So I'm back to here and want to still use this change. I not use "update
PcdSpinLockTimeout to 0 in platform" solution because I think core driver
depends on platform policy is not a good design.
Do you guys have any other concern?
Thanks,
Eric
> -Original Message-
> From: Brian J. Johnson [mailto:brian.john...@hpe.com]
> Sent: Friday, December 21, 2018 12:36 AM
> To: Yao, Jiewen ; Ni, Ruiyu ;
> Dong, Eric ; edk2-devel@lists.01.org
> Cc: Laszlo Ersek
> Subject: Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> AP calls PeiService.
>
> Agreed. We've seen issues on real platforms with timed-out spinlocks in DXE
> causing calls to GetPerformanceCounter and DebugAssert. (DXE has the
> same code, with the same issues.)
>
> Note that it's possible to set PcdSpinLockTimeout=0 to work around the issue
> on a particular platform, or in a particular module. But if you have to do
> that
> for every module which uses APs, and hence could contend for a spinlock, it
> kind of defeats the point We're better off removing the timeout code.
>
> Thanks,
> Brian
>
> On 12/19/18 8:08 PM, Yao, Jiewen wrote:
> > Yes, I agree, if we don't have any real case.
> >
> >
> >> -Original Message-
> >> From: Ni, Ruiyu
> >> Sent: Thursday, December 20, 2018 10:07 AM
> >> To: Dong, Eric ; Yao, Jiewen
> >> ; edk2-devel@lists.01.org
> >> Cc: Laszlo Ersek
> >> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >> Avoid AP calls PeiService.
> >>
> >> Can you just change the AcquireSpinLock() behavior to remove the
> >> Timeout PCD consumption?
> >>
> >> I haven't seen a real case that the timed acquisition of spin lock is
> >> needed.
> >>
> >>
> >> Thanks/Ray
> >>
> >>> -Original Message-
> >>> From: Dong, Eric
> >>> Sent: Thursday, December 20, 2018 9:23 AM
> >>> To: Yao, Jiewen ; edk2-devel@lists.01.org
> >>> Cc: Ni, Ruiyu ; Laszlo Ersek
> >>> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >>> Avoid AP calls PeiService.
> >>>
> >>>
> >>> Agreed, Maybe it's time to add a new API like
> >>> AcquireSpinLockWithoutTimeOut?
> >>>
> >>> Thanks,
> >>> Eric
> >>>> -Original Message-
> >>>> From: Yao, Jiewen
> >>>> Sent: Thursday, December 20, 2018 9:19 AM
> >>>> To: Dong, Eric ; edk2-devel@lists.01.org
> >>>> Cc: Ni, Ruiyu ; Laszlo Ersek
> >>>>
> >>>> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >>>> Avoid AP calls PeiService.
> >>>>
> >>>> Hi
> >>>> If we think below code is generic, can we have an API for that?
> >>>>
> >>>> + //
> >>>> + // Wait for the AP to release the MSR spin lock.
> >>>> + //
> >>>> + while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> >>>> +CpuPause ();
> >>>> + }
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>> -Original Message-
> >>>>> From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On
> >>>>> Behalf Of Eric Dong
> >>>>> Sent: Thursday, December 20, 2018 9:16 AM
> >>>>> To: edk2-devel@lists.01.org
> >>>>> Cc: Ni, Ruiyu ; Laszlo Ersek
> >>>>>
> >>>>> Subject: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >>>>> Avoid AP calls PeiService.
> >>>>>
> >>>>> In AcquireSpinLock function, it calls GetPerformanceCounter which
> >>>>> final calls PeiService service. This patch avoid to call
> >>>>> AcquireSpinLock function.
> >>>>>
> >>>>> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1411
> >>>>>
> >>>>> Cc: Ruiyu Ni
> >>>>> Cc: Laszlo Ersek
> >>>>> Contributed-under: TianoCore Contribution Agreement 1.1
> >>>>> Signed-off-by: Eric Dong
> >>>>> ---
> >>>>>
> >
Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
Hi,
Thanks all for your comments. It's valuable to me.
Seems like we all agree to remove the PcdSpinLockTimeout in AcquireSpinLock. I
have submit BZ for it:
https://bugzilla.tianocore.org/show_bug.cgi?id=1419
For my patch, I will avoid this code change and set PcdSpinLockTimeout=0 for
my modules. I will send V2 patch soon.
Thanks,
Eric
> -Original Message-
> From: Brian J. Johnson [mailto:brian.john...@hpe.com]
> Sent: Friday, December 21, 2018 12:36 AM
> To: Yao, Jiewen ; Ni, Ruiyu ;
> Dong, Eric ; edk2-devel@lists.01.org
> Cc: Laszlo Ersek
> Subject: Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> AP calls PeiService.
>
> Agreed. We've seen issues on real platforms with timed-out spinlocks in DXE
> causing calls to GetPerformanceCounter and DebugAssert. (DXE has the
> same code, with the same issues.)
>
> Note that it's possible to set PcdSpinLockTimeout=0 to work around the issue
> on a particular platform, or in a particular module. But if you have to do
> that
> for every module which uses APs, and hence could contend for a spinlock, it
> kind of defeats the point We're better off removing the timeout code.
>
> Thanks,
> Brian
>
> On 12/19/18 8:08 PM, Yao, Jiewen wrote:
> > Yes, I agree, if we don't have any real case.
> >
> >
> >> -Original Message-
> >> From: Ni, Ruiyu
> >> Sent: Thursday, December 20, 2018 10:07 AM
> >> To: Dong, Eric ; Yao, Jiewen
> >> ; edk2-devel@lists.01.org
> >> Cc: Laszlo Ersek
> >> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >> Avoid AP calls PeiService.
> >>
> >> Can you just change the AcquireSpinLock() behavior to remove the
> >> Timeout PCD consumption?
> >>
> >> I haven't seen a real case that the timed acquisition of spin lock is
> >> needed.
> >>
> >>
> >> Thanks/Ray
> >>
> >>> -Original Message-
> >>> From: Dong, Eric
> >>> Sent: Thursday, December 20, 2018 9:23 AM
> >>> To: Yao, Jiewen ; edk2-devel@lists.01.org
> >>> Cc: Ni, Ruiyu ; Laszlo Ersek
> >>> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >>> Avoid AP calls PeiService.
> >>>
> >>>
> >>> Agreed, Maybe it's time to add a new API like
> >>> AcquireSpinLockWithoutTimeOut?
> >>>
> >>> Thanks,
> >>> Eric
> >>>> -Original Message-
> >>>> From: Yao, Jiewen
> >>>> Sent: Thursday, December 20, 2018 9:19 AM
> >>>> To: Dong, Eric ; edk2-devel@lists.01.org
> >>>> Cc: Ni, Ruiyu ; Laszlo Ersek
> >>>>
> >>>> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >>>> Avoid AP calls PeiService.
> >>>>
> >>>> Hi
> >>>> If we think below code is generic, can we have an API for that?
> >>>>
> >>>> + //
> >>>> + // Wait for the AP to release the MSR spin lock.
> >>>> + //
> >>>> + while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> >>>> +CpuPause ();
> >>>> + }
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>> -Original Message-
> >>>>> From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On
> >>>>> Behalf Of Eric Dong
> >>>>> Sent: Thursday, December 20, 2018 9:16 AM
> >>>>> To: edk2-devel@lists.01.org
> >>>>> Cc: Ni, Ruiyu ; Laszlo Ersek
> >>>>>
> >>>>> Subject: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> >>>>> Avoid AP calls PeiService.
> >>>>>
> >>>>> In AcquireSpinLock function, it calls GetPerformanceCounter which
> >>>>> final calls PeiService service. This patch avoid to call
> >>>>> AcquireSpinLock function.
> >>>>>
> >>>>> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1411
> >>>>>
> >>>>> Cc: Ruiyu Ni
> >>>>> Cc: Laszlo Ersek
> >>>>> Contributed-under: TianoCore Contribution Agreement 1.1
> >>>>> Signed-off-by: Eric Dong
> >>>>> ---
> >>>>>
> >>>>> UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> >>>>>
Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
Agreed. We've seen issues on real platforms with timed-out spinlocks in
DXE causing calls to GetPerformanceCounter and DebugAssert. (DXE has
the same code, with the same issues.)
Note that it's possible to set PcdSpinLockTimeout=0 to work around the
issue on a particular platform, or in a particular module. But if you
have to do that for every module which uses APs, and hence could contend
for a spinlock, it kind of defeats the point We're better off
removing the timeout code.
Thanks,
Brian
On 12/19/18 8:08 PM, Yao, Jiewen wrote:
Yes, I agree, if we don't have any real case.
-Original Message-
From: Ni, Ruiyu
Sent: Thursday, December 20, 2018 10:07 AM
To: Dong, Eric ; Yao, Jiewen
; edk2-devel@lists.01.org
Cc: Laszlo Ersek
Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
AP calls PeiService.
Can you just change the AcquireSpinLock() behavior to remove the Timeout
PCD consumption?
I haven't seen a real case that the timed acquisition of spin lock is needed.
Thanks/Ray
-Original Message-
From: Dong, Eric
Sent: Thursday, December 20, 2018 9:23 AM
To: Yao, Jiewen ; edk2-devel@lists.01.org
Cc: Ni, Ruiyu ; Laszlo Ersek
Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
AP calls PeiService.
Agreed, Maybe it's time to add a new API like
AcquireSpinLockWithoutTimeOut?
Thanks,
Eric
-Original Message-
From: Yao, Jiewen
Sent: Thursday, December 20, 2018 9:19 AM
To: Dong, Eric ; edk2-devel@lists.01.org
Cc: Ni, Ruiyu ; Laszlo Ersek
Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
Avoid AP calls PeiService.
Hi
If we think below code is generic, can we have an API for that?
+ //
+ // Wait for the AP to release the MSR spin lock.
+ //
+ while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
+CpuPause ();
+ }
-Original Message-
From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf
Of Eric Dong
Sent: Thursday, December 20, 2018 9:16 AM
To: edk2-devel@lists.01.org
Cc: Ni, Ruiyu ; Laszlo Ersek
Subject: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
AP calls PeiService.
In AcquireSpinLock function, it calls GetPerformanceCounter which
final calls PeiService service. This patch avoid to call
AcquireSpinLock function.
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1411
Cc: Ruiyu Ni
Cc: Laszlo Ersek
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong
---
UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c |
7
++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git
a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
index 624ddee055..a64326239f 100644
---
a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
+++
b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.
+++ c
@@ -832,7 +832,12 @@ ProgramProcessorRegister (
RegisterTableEntry = &RegisterTableEntryHead[Index];
DEBUG_CODE_BEGIN ();
- AcquireSpinLock (&CpuFlags->ConsoleLogLock);
+ //
+ // Wait for the AP to release the MSR spin lock.
+ //
+ while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
+CpuPause ();
+ }
ThreadIndex = ApLocation->Package *
CpuStatus->MaxCoreCount *
CpuStatus->MaxThreadCount +
ApLocation->Core * CpuStatus->MaxThreadCount +
ApLocation->Thread;
--
2.15.0.windows.1
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Brian J. Johnson
Enterprise X86 Lab
Hewlett Packard Enterprise
brian.john...@hpe.com
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Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
Yes, I agree, if we don't have any real case.
> -Original Message-
> From: Ni, Ruiyu
> Sent: Thursday, December 20, 2018 10:07 AM
> To: Dong, Eric ; Yao, Jiewen
> ; edk2-devel@lists.01.org
> Cc: Laszlo Ersek
> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> AP calls PeiService.
>
> Can you just change the AcquireSpinLock() behavior to remove the Timeout
> PCD consumption?
>
> I haven't seen a real case that the timed acquisition of spin lock is needed.
>
>
> Thanks/Ray
>
> > -Original Message-
> > From: Dong, Eric
> > Sent: Thursday, December 20, 2018 9:23 AM
> > To: Yao, Jiewen ; edk2-devel@lists.01.org
> > Cc: Ni, Ruiyu ; Laszlo Ersek
> > Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> > AP calls PeiService.
> >
> >
> > Agreed, Maybe it's time to add a new API like
> > AcquireSpinLockWithoutTimeOut?
> >
> > Thanks,
> > Eric
> > > -Original Message-
> > > From: Yao, Jiewen
> > > Sent: Thursday, December 20, 2018 9:19 AM
> > > To: Dong, Eric ; edk2-devel@lists.01.org
> > > Cc: Ni, Ruiyu ; Laszlo Ersek
> > > Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> > > Avoid AP calls PeiService.
> > >
> > > Hi
> > > If we think below code is generic, can we have an API for that?
> > >
> > > + //
> > > + // Wait for the AP to release the MSR spin lock.
> > > + //
> > > + while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> > > +CpuPause ();
> > > + }
> > >
> > >
> > >
> > >
> > > > -Original Message-
> > > > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf
> > > > Of Eric Dong
> > > > Sent: Thursday, December 20, 2018 9:16 AM
> > > > To: edk2-devel@lists.01.org
> > > > Cc: Ni, Ruiyu ; Laszlo Ersek
> > > > Subject: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> > > > AP calls PeiService.
> > > >
> > > > In AcquireSpinLock function, it calls GetPerformanceCounter which
> > > > final calls PeiService service. This patch avoid to call
> > > > AcquireSpinLock function.
> > > >
> > > > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1411
> > > >
> > > > Cc: Ruiyu Ni
> > > > Cc: Laszlo Ersek
> > > > Contributed-under: TianoCore Contribution Agreement 1.1
> > > > Signed-off-by: Eric Dong
> > > > ---
> > > > UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c |
> > > > 7
> > > > ++-
> > > > 1 file changed, 6 insertions(+), 1 deletion(-)
> > > >
> > > > diff --git
> > > > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > > b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > > index 624ddee055..a64326239f 100644
> > > > ---
> > > > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > > +++
> b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.
> > > > +++ c
> > > > @@ -832,7 +832,12 @@ ProgramProcessorRegister (
> > > > RegisterTableEntry = &RegisterTableEntryHead[Index];
> > > >
> > > > DEBUG_CODE_BEGIN ();
> > > > - AcquireSpinLock (&CpuFlags->ConsoleLogLock);
> > > > + //
> > > > + // Wait for the AP to release the MSR spin lock.
> > > > + //
> > > > + while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> > > > +CpuPause ();
> > > > + }
> > > >ThreadIndex = ApLocation->Package *
> CpuStatus->MaxCoreCount *
> > > > CpuStatus->MaxThreadCount +
> > > >ApLocation->Core * CpuStatus->MaxThreadCount +
> > > >ApLocation->Thread;
> > > > --
> > > > 2.15.0.windows.1
> > > >
> > > > ___
> > > > edk2-devel mailing list
> > > > edk2-devel@lists.01.org
> > > > https://lists.01.org/mailman/listinfo/edk2-devel
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Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
Can you just change the AcquireSpinLock() behavior to remove the Timeout PCD
consumption?
I haven't seen a real case that the timed acquisition of spin lock is needed.
Thanks/Ray
> -Original Message-
> From: Dong, Eric
> Sent: Thursday, December 20, 2018 9:23 AM
> To: Yao, Jiewen ; edk2-devel@lists.01.org
> Cc: Ni, Ruiyu ; Laszlo Ersek
> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> AP calls PeiService.
>
>
> Agreed, Maybe it's time to add a new API like
> AcquireSpinLockWithoutTimeOut?
>
> Thanks,
> Eric
> > -Original Message-
> > From: Yao, Jiewen
> > Sent: Thursday, December 20, 2018 9:19 AM
> > To: Dong, Eric ; edk2-devel@lists.01.org
> > Cc: Ni, Ruiyu ; Laszlo Ersek
> > Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib:
> > Avoid AP calls PeiService.
> >
> > Hi
> > If we think below code is generic, can we have an API for that?
> >
> > + //
> > + // Wait for the AP to release the MSR spin lock.
> > + //
> > + while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> > +CpuPause ();
> > + }
> >
> >
> >
> >
> > > -Original Message-
> > > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf
> > > Of Eric Dong
> > > Sent: Thursday, December 20, 2018 9:16 AM
> > > To: edk2-devel@lists.01.org
> > > Cc: Ni, Ruiyu ; Laszlo Ersek
> > > Subject: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> > > AP calls PeiService.
> > >
> > > In AcquireSpinLock function, it calls GetPerformanceCounter which
> > > final calls PeiService service. This patch avoid to call
> > > AcquireSpinLock function.
> > >
> > > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1411
> > >
> > > Cc: Ruiyu Ni
> > > Cc: Laszlo Ersek
> > > Contributed-under: TianoCore Contribution Agreement 1.1
> > > Signed-off-by: Eric Dong
> > > ---
> > > UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c |
> > > 7
> > > ++-
> > > 1 file changed, 6 insertions(+), 1 deletion(-)
> > >
> > > diff --git
> > > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > index 624ddee055..a64326239f 100644
> > > ---
> > > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > > +++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.
> > > +++ c
> > > @@ -832,7 +832,12 @@ ProgramProcessorRegister (
> > > RegisterTableEntry = &RegisterTableEntryHead[Index];
> > >
> > > DEBUG_CODE_BEGIN ();
> > > - AcquireSpinLock (&CpuFlags->ConsoleLogLock);
> > > + //
> > > + // Wait for the AP to release the MSR spin lock.
> > > + //
> > > + while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> > > +CpuPause ();
> > > + }
> > >ThreadIndex = ApLocation->Package * CpuStatus->MaxCoreCount *
> > > CpuStatus->MaxThreadCount +
> > >ApLocation->Core * CpuStatus->MaxThreadCount +
> > >ApLocation->Thread;
> > > --
> > > 2.15.0.windows.1
> > >
> > > ___
> > > edk2-devel mailing list
> > > edk2-devel@lists.01.org
> > > https://lists.01.org/mailman/listinfo/edk2-devel
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Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
Agreed, Maybe it's time to add a new API like AcquireSpinLockWithoutTimeOut?
Thanks,
Eric
> -Original Message-
> From: Yao, Jiewen
> Sent: Thursday, December 20, 2018 9:19 AM
> To: Dong, Eric ; edk2-devel@lists.01.org
> Cc: Ni, Ruiyu ; Laszlo Ersek
> Subject: RE: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> AP calls PeiService.
>
> Hi
> If we think below code is generic, can we have an API for that?
>
> + //
> + // Wait for the AP to release the MSR spin lock.
> + //
> + while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> +CpuPause ();
> + }
>
>
>
>
> > -Original Message-
> > From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of
> > Eric Dong
> > Sent: Thursday, December 20, 2018 9:16 AM
> > To: edk2-devel@lists.01.org
> > Cc: Ni, Ruiyu ; Laszlo Ersek
> > Subject: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid
> > AP calls PeiService.
> >
> > In AcquireSpinLock function, it calls GetPerformanceCounter which
> > final calls PeiService service. This patch avoid to call
> > AcquireSpinLock function.
> >
> > BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1411
> >
> > Cc: Ruiyu Ni
> > Cc: Laszlo Ersek
> > Contributed-under: TianoCore Contribution Agreement 1.1
> > Signed-off-by: Eric Dong
> > ---
> > UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c | 7
> > ++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git
> > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > index 624ddee055..a64326239f 100644
> > ---
> > a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> > +++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.
> > +++ c
> > @@ -832,7 +832,12 @@ ProgramProcessorRegister (
> > RegisterTableEntry = &RegisterTableEntryHead[Index];
> >
> > DEBUG_CODE_BEGIN ();
> > - AcquireSpinLock (&CpuFlags->ConsoleLogLock);
> > + //
> > + // Wait for the AP to release the MSR spin lock.
> > + //
> > + while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> > +CpuPause ();
> > + }
> >ThreadIndex = ApLocation->Package * CpuStatus->MaxCoreCount *
> > CpuStatus->MaxThreadCount +
> >ApLocation->Core * CpuStatus->MaxThreadCount +
> >ApLocation->Thread;
> > --
> > 2.15.0.windows.1
> >
> > ___
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> > edk2-devel@lists.01.org
> > https://lists.01.org/mailman/listinfo/edk2-devel
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Re: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
Hi
If we think below code is generic, can we have an API for that?
+ //
+ // Wait for the AP to release the MSR spin lock.
+ //
+ while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
+CpuPause ();
+ }
> -Original Message-
> From: edk2-devel [mailto:edk2-devel-boun...@lists.01.org] On Behalf Of
> Eric Dong
> Sent: Thursday, December 20, 2018 9:16 AM
> To: edk2-devel@lists.01.org
> Cc: Ni, Ruiyu ; Laszlo Ersek
> Subject: [edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP
> calls PeiService.
>
> In AcquireSpinLock function, it calls GetPerformanceCounter which
> final calls PeiService service. This patch avoid to call
> AcquireSpinLock function.
>
> BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1411
>
> Cc: Ruiyu Ni
> Cc: Laszlo Ersek
> Contributed-under: TianoCore Contribution Agreement 1.1
> Signed-off-by: Eric Dong
> ---
> UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c | 7
> ++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git
> a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> index 624ddee055..a64326239f 100644
> --- a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> +++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
> @@ -832,7 +832,12 @@ ProgramProcessorRegister (
> RegisterTableEntry = &RegisterTableEntryHead[Index];
>
> DEBUG_CODE_BEGIN ();
> - AcquireSpinLock (&CpuFlags->ConsoleLogLock);
> + //
> + // Wait for the AP to release the MSR spin lock.
> + //
> + while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
> +CpuPause ();
> + }
>ThreadIndex = ApLocation->Package * CpuStatus->MaxCoreCount *
> CpuStatus->MaxThreadCount +
>ApLocation->Core * CpuStatus->MaxThreadCount +
>ApLocation->Thread;
> --
> 2.15.0.windows.1
>
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[edk2] [Patch 1/3] UefiCpuPkg/RegisterCpuFeaturesLib: Avoid AP calls PeiService.
In AcquireSpinLock function, it calls GetPerformanceCounter which
final calls PeiService service. This patch avoid to call
AcquireSpinLock function.
BZ: https://bugzilla.tianocore.org/show_bug.cgi?id=1411
Cc: Ruiyu Ni
Cc: Laszlo Ersek
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong
---
UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c | 7 ++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
index 624ddee055..a64326239f 100644
--- a/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
+++ b/UefiCpuPkg/Library/RegisterCpuFeaturesLib/CpuFeaturesInitialize.c
@@ -832,7 +832,12 @@ ProgramProcessorRegister (
RegisterTableEntry = &RegisterTableEntryHead[Index];
DEBUG_CODE_BEGIN ();
- AcquireSpinLock (&CpuFlags->ConsoleLogLock);
+ //
+ // Wait for the AP to release the MSR spin lock.
+ //
+ while (!AcquireSpinLockOrFail (&CpuFlags->ConsoleLogLock)) {
+CpuPause ();
+ }
ThreadIndex = ApLocation->Package * CpuStatus->MaxCoreCount *
CpuStatus->MaxThreadCount +
ApLocation->Core * CpuStatus->MaxThreadCount +
ApLocation->Thread;
--
2.15.0.windows.1
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