git: 0a0c599ab9a5 - main - hwpmc(4): remove paragraph about Pentium Pro handling
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Date: Fri, 16 Jun 2023 16:45:05 UTC
The branch main has been updated by mhorne: URL: https://cgit.FreeBSD.org/src/commit/?id=0a0c599ab9a578dd175e626144eacdbb4c5ac6bc commit 0a0c599ab9a578dd175e626144eacdbb4c5ac6bc Author: Mitchell Horne <mhorne@FreeBSD.org> AuthorDate: 2023-06-16 16:34:02 +0000 Commit: Mitchell Horne <mhorne@FreeBSD.org> CommitDate: 2023-06-16 16:44:53 +0000 hwpmc(4): remove paragraph about Pentium Pro handling Support for these CPUs was removed in 2018 (e92a1350b50e). Reviewed by: jkoshy, emaste MFC after: 1 week Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D40541 --- share/man/man4/hwpmc.4 | 22 ---------------------- 1 file changed, 22 deletions(-) diff --git a/share/man/man4/hwpmc.4 b/share/man/man4/hwpmc.4 index 05fecf816a10..de38041bf640 100644 --- a/share/man/man4/hwpmc.4 +++ b/share/man/man4/hwpmc.4 @@ -473,28 +473,6 @@ PMCs, then the driver will reject allocation requests for process-private PMCs that request counting of hardware events that cannot be counted separately for each logical CPU. -.Ss Intel Pentium-Pro Handling -Writing a value to the PMC MSRs found in Intel Pentium-Pro style PMCs -(found in -.Tn "Intel Pentium Pro" , -.Tn "Pentium II" , -.Tn "Pentium III" , -.Tn "Pentium M" -and -.Tn "Celeron" -processors) will replicate bit 31 of the -value being written into the upper 8 bits of the MSR, -bringing down the usable width of these PMCs to 31 bits. -For process-virtual PMCs, the -.Nm -driver implements a workaround in software and makes the corrected 64 -bit count available via the -.Dv PMC_OP_RW -operation. -Processes that intend to use RDPMC instructions directly or -that intend to write values larger than 2^31 into these PMCs with -.Dv PMC_OP_RW -need to be aware of this hardware limitation. .Sh DIAGNOSTICS .Bl -diag .It "hwpmc: [class/npmc/capabilities]..."