Date: Mon, 27 Jan 2020 02:49:38 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 234733] Setting CPU frequency with sysctl dev.cpu.0.fr slows a Ryzen 2700X down Message-ID: <bug-234733-227-k74yXNJTY5@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-234733-227@https.bugs.freebsd.org/bugzilla/> References: <bug-234733-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=234733 --- Comment #9 from Conrad Meyer <cem@freebsd.org> --- Another test to try (maybe after entering a non-P0 p-state, not sure if that matters) if you'd like: $ cpucontrol -m '0xc0010061' /dev/cpuctl0 This is the PStateCurLim register, and the low 3 bits are 'CurPstateLimit'. It represents the highest performance P-state the processor is (currently) allowed to enter. I don't know why it would be non-zero if the processor is in P0 at boot, but I suppose it could be a BIOS issue. Finally, you could try just manually checking the last set P-state: $ cpucontrol -m '0xc0010062' /dev/cpuctl0 (Last-set P-state is the low 3 bits of that register.) Or setting P-state 0 across all cpus manually, bypassing hwpstate(4): $ for i in $(jot 16 0) ; do cpucontrol -m '0xc0010062=0x0' /dev/cpuctl$i ; done (Bourne sh; I don't know if that works in csh or anything exotic.) -- You are receiving this mail because: You are the assignee for the bug.help
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