Date: Mon, 27 Jan 2020 07:31:03 +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-asbqtm5QYH@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=3D234733 --- Comment #18 from Conrad Meyer <cem@freebsd.org> --- (In reply to sigsys from comment #15) > It would already be pretty good if the kernel could detect the situation = by > double checking on one of those registers and log a warning. Assuming it > wouldn't risk causing even more problems on some other systems. We used to verify set P-state on all cpus prior to r326383. It gets pretty inefficient to check all cores. Checking just one only tells you one made = it to the configured P-state. (AMD P-states are independent across each core;= SMT threads share a P-state domain.) But that's not really the situation here; here we're restricting P-state ourselves in software due to the (seemingly bogus) c0010061 limit. In this case, I added a debug log in the commit referenced in comment #17. I am curious if Linux does any better. Maybe they just ignore c0010061. (In reply to sigsys from comment #16) That's unfortunate :-(. --=20 You are receiving this mail because: You are the assignee for the bug.=
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