This new PCD is used to specify the AP C-state value by MWAIT instruction. More deeper C-state means more longer latency time when APs exiting from MWAIT state. Platforms need to balance the performance and power saving to find the proper C-state for APs.
Also, some processor may not ready for the deepest C-state at the beginning. Platform also could choose the proper chance to place AP into the deeper C-state by set this PCD before hand-off to OS. Contributed-under: TianoCore Contribution Agreement 1.0 Cc: Feng Tian <[email protected]> Cc: Michael Kinney <[email protected]> Cc: Jordan Justen <[email protected]> Contributed-under: TianoCore Contribution Agreement 1.0 Signed-off-by: Jeff Fan <[email protected]> --- UefiCpuPkg/UefiCpuPkg.dec | 5 +++++ UefiCpuPkg/UefiCpuPkg.uni | Bin 22980 -> 23534 bytes 2 files changed, 5 insertions(+) diff --git a/UefiCpuPkg/UefiCpuPkg.dec b/UefiCpuPkg/UefiCpuPkg.dec index 0d42918..472b38a 100644 --- a/UefiCpuPkg/UefiCpuPkg.dec +++ b/UefiCpuPkg/UefiCpuPkg.dec @@ -190,6 +190,11 @@ # @Prompt The AP wait loop state. # @ValidRange 0x80000001 | 1 - 3 gUefiCpuPkgTokenSpaceGuid.PcdCpuApLoopMode|1|UINT8|0x60008006 + ## Specifies the AP target C-state for Mwait during POST phase. + # The default value 0 means C1 state. + # The value is defined as below.<BR><BR> + # @Prompt The specified AP target C-state for Mwait. + gUefiCpuPkgTokenSpaceGuid.PcdCpuApTargetCstate|0|UINT8|0x00000007 [PcdsDynamic, PcdsDynamicEx] ## Contains the pointer to a CPU S3 data buffer of structure ACPI_CPU_DATA. diff --git a/UefiCpuPkg/UefiCpuPkg.uni b/UefiCpuPkg/UefiCpuPkg.uni index b4c5376ca8c14132dcd12c30f0c1499599195d48..9fbc7310fd30d3349fc2c9a6b26029cc6f739b2f 100644 GIT binary patch delta 203 zcmX@Inep9r#tlazCm)cAm@E*<A{xSw$WX+P&XCGb!r;tM3?vg7N+ugRnonL6$l+Pc zPym!kX2@hn1L9PM6b1zbM}`0(2~r2srvTKc3)2f!r2tf&50q74@MS0ms>=kL=*XXr Q!!E_hP<>KOn;dBf0QUqgOaK4? delta 9 QcmaF2o$<(K#tlaz0U9y{>;M1& -- 1.9.5.msysgit.0 _______________________________________________ edk2-devel mailing list [email protected] https://lists.01.org/mailman/listinfo/edk2-devel
