Date: Tue, 28 Feb 2017 15:55:16 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-virtualization@FreeBSD.org Subject: [Bug 216759] [kern] Memory speed with small blocks (1K) up to 35 times slower than host system (under QEMU emulation, but not only) Message-ID: <bug-216759-27103-gA5XQCWLy7@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-216759-27103@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=216759 --- Comment #10 from andrew@azar-a.net --- About linux, seems kvm-clock is broken somehow, I adjusted to TSC and got 3700 of the host... And it seems same is for FreeBSD. Only BSD forces HPET or ACPI on any virtualised platform. So there is only manual way to force to TSC-low which brings us back to 3700 Seems like kernel timecounters code has been written in times of just appearing invariant_tsc and it does not know anything about CPU flags constant_tsc nonstop_tsc tsc_deadline_timer etc... It's really simple in code. If it's invariant or SMP it's boosted... and that's it: https://github.com/freebsd/freebsd/blob/21c11d113415f2c87107b6735407b147fae0b851/sys/x86/x86/tsc.c -- You are receiving this mail because: You are the assignee for the bug.home | help
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