Re: [PATCH v2] UefiCpuPkg/MpInitLib DXE: Add PCD to control AP status check interval


Zeng, Star
 

The code logic is good to me.
Only minor concern, do we really need the PCD to be UINT64 type? :)

Thanks,
Star

-----Original Message-----
From: devel@edk2.groups.io [mailto:devel@edk2.groups.io] On Behalf Of
Wu, Hao A
Sent: Tuesday, March 24, 2020 2:33 PM
To: devel@edk2.groups.io
Cc: Wu, Hao A <hao.a.wu@...>; Dong, Eric <eric.dong@...>; Ni,
Ray <ray.ni@...>; Laszlo Ersek <lersek@...>; Kinney, Michael
D <michael.d.kinney@...>; Zeng, Star <star.zeng@...>; Brian J .
Johnson <brian.johnson@...>
Subject: [edk2-devel] [PATCH v2] UefiCpuPkg/MpInitLib DXE: Add PCD to
control AP status check interval

REF:https://bugzilla.tianocore.org/show_bug.cgi?id=2627

The commit will introduce a static PCD to specify the periodic interval for
checking the AP status when MP services StartupAllAPs() and
StartupThisAP() are being executed in a non-blocking manner. Or in other
words, specifies the interval for callback function CheckApsStatus().

The purpose is to provide the platform owners with the ability to choose the
proper interval value to trigger CheckApsStatus() according to:
A) The number of processors in the system;
B) How MP services (StartupAllAPs & StartupThisAP) being used.

Setting the PCD to a small value means the AP status check callback will be
trigerred more frequently, it can benefit the performance for the case when
the BSP uses WaitForEvent() or uses CheckEvent() in a loop to wait for AP(s)
to complete the task, especially when the task can be finished considerably
fast on AP(s).

An example is within function CpuFeaturesInitialize() under
UefiCpuPkg/Library/RegisterCpuFeaturesLib/DxeRegisterCpuFeaturesLib.c,
where BSP will perform the same task with APs and requires all the
processors to finish the task before BSP proceeds to its next task.

Setting the PCD to a big value, on the other hand, can reduce the impact on
BSP by the time being consumed in CheckApsStatus(), especially when the
number of processors is huge so that the time consumed in CheckApsStatus()
is not negligible.

For least impact, the default value of the new PCD will be the same with the
current interval value, which is 100 milliseconds.

Unitest done:
OS boot successfully.

Cc: Eric Dong <eric.dong@...>
Cc: Ray Ni <ray.ni@...>
Cc: Laszlo Ersek <lersek@...>
Cc: Michael D Kinney <michael.d.kinney@...>
Cc: Star Zeng <star.zeng@...>
Cc: Brian J. Johnson <brian.johnson@...>
Signed-off-by: Hao A Wu <hao.a.wu@...>
---
UefiCpuPkg/UefiCpuPkg.dec | 6 ++++++
UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf | 2 +-
UefiCpuPkg/Library/MpInitLib/DxeMpLib.c | 3 +--
UefiCpuPkg/UefiCpuPkg.uni | 5 ++++-
4 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec index
e91dc68cbe..06a3d52060 100644
--- a/UefiCpuPkg/UefiCpuPkg.dec
+++ b/UefiCpuPkg/UefiCpuPkg.dec
@@ -230,6 +230,12 @@ [PcdsFixedAtBuild, PcdsPatchableInModule]
# @Prompt This PCD is the nominal frequency of the core crystal clock in Hz
as is CPUID Leaf 0x15:ECX

gUefiCpuPkgTokenSpaceGuid.PcdCpuCoreCrystalClockFrequency|24000000|
UINT64|0x32132113

+ ## Specifies the periodic interval value in milliseconds for the
+ status check # of APs for StartupAllAPs() and StartupThisAP()
+ executed in non-blocking # mode in DXE phase.
+ # @Prompt Periodic interval value in milliseconds for AP status check in
DXE.
+
+
gUefiCpuPkgTokenSpaceGuid.PcdCpuApStatusCheckInterval|100|UINT64|0x
000
+ 0001E
+
[PcdsFixedAtBuild, PcdsPatchableInModule, PcdsDynamic, PcdsDynamicEx]
## Specifies max supported number of Logical Processors.
# @Prompt Configure max supported number of Logical Processors diff --git
a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
index 45aaa179ff..05e004dc3c 100644
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpInitLib.inf
@@ -69,5 +69,5 @@ [Pcd]
gUefiCpuPkgTokenSpaceGuid.PcdCpuMicrocodePatchRegionSize ##
CONSUMES
gUefiCpuPkgTokenSpaceGuid.PcdCpuApLoopMode ##
CONSUMES
gUefiCpuPkgTokenSpaceGuid.PcdCpuApTargetCstate ##
SOMETIMES_CONSUMES
+ gUefiCpuPkgTokenSpaceGuid.PcdCpuApStatusCheckInterval ##
CONSUMES
gEfiMdeModulePkgTokenSpaceGuid.PcdCpuStackGuard ##
CONSUMES
-
diff --git a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
index a987c32109..683547dc99 100644
--- a/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
+++ b/UefiCpuPkg/Library/MpInitLib/DxeMpLib.c
@@ -15,7 +15,6 @@

#include <Protocol/Timer.h>

-#define AP_CHECK_INTERVAL (EFI_TIMER_PERIOD_MILLISECONDS (100))
#define AP_SAFE_STACK_SIZE 128

CPU_MP_DATA *mCpuMpData = NULL;
@@ -451,7 +450,7 @@ InitMpGlobalData (
Status = gBS->SetTimer (
mCheckAllApsEvent,
TimerPeriodic,
- AP_CHECK_INTERVAL
+ PcdGet64 (PcdCpuApStatusCheckInterval)
);
ASSERT_EFI_ERROR (Status);

diff --git a/UefiCpuPkg/UefiCpuPkg.uni b/UefiCpuPkg/UefiCpuPkg.uni index
c0d6ed5136..08d9b45f76 100644
--- a/UefiCpuPkg/UefiCpuPkg.uni
+++ b/UefiCpuPkg/UefiCpuPkg.uni
@@ -3,7 +3,7 @@
//
// This Package provides UEFI compatible CPU modules and libraries.
//
-// Copyright (c) 2007 - 2015, Intel Corporation. All rights reserved.<BR>
+// Copyright (c) 2007 - 2020, Intel Corporation. All rights
+reserved.<BR>
//
// SPDX-License-Identifier: BSD-2-Clause-Patent // @@ -275,3 +275,6 @@
#string
STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuSmmMpTokenCountPerChunk_PR
OMPT #language en-US "Specify the count of pre allocated SMM MP tokens
per chunk.\n"

#string
STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuSmmMpTokenCountPerChunk_HE
LP #language en-US "This value used to specify the count of pre allocated
SMM MP tokens per chunk.\n"
+
+#string
STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuApStatusCheckInterval_PROMPT
#language en-US "Periodic interval value in milliseconds for AP status check in
DXE.\n"
+#string
STR_gUefiCpuPkgTokenSpaceGuid_PcdCpuApStatusCheckInterval_HELP
#language en-US "Periodic interval value in milliseconds for the status check
of APs for StartupAllAPs() and StartupThisAP() executed in non-blocking
mode in DXE phase.\n"
--
2.12.0.windows.1


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