Date: Wed, 10 Feb 2016 21:47:03 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-bugs@FreeBSD.org Subject: [Bug 207068] hwpmc wrap around/sign extension Message-ID: <bug-207068-8-79zzn3RN4B@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-207068-8@https.bugs.freebsd.org/bugzilla/> References: <bug-207068-8@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D207068 --- Comment #5 from joss.upton@yahoo.com --- (In reply to Konstantin Belousov from comment #4) I don't know if Sandy Bridge supports the aliases or not. I do know that vmware fusion on my Broadwell machine does NOT support the IA32_A_PMCn registers and thus will panic. Note you may also need other processes using the PMC to be scheduled/unscheduled to reproduce... You have to catch a case where it wri= tes with EAX[31]=3D1 to IA32_PMCn. This results in an automatic sign extension= (as described in the Intel arch manual, 18.2.2.3 Full-Width Writes to Performan= ce Counter Registers) and ignores EDX completely. --=20 You are receiving this mail because: You are the assignee for the bug.=
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