Commit 4c27625b authored May 05, 2018 by Wanpeng Li Committed by Paolo Bonzini May 15, 2018

KVM: X86: Lower the default timer frequency limit to 200us



Anthoine reported:
 The period used by Windows change over time but it can be 1
 milliseconds or less. I saw the limit_periodic_timer_frequency
 print so 500 microseconds is sometimes reached.

As suggested by Paolo, lower the default timer frequency limit to a
smaller interval of 200 us (5000 Hz) to leave some headroom. This
is required due to Windows 10 changing the scheduler tick limit
from 1024 Hz to 2048 Hz.

Reported-by: Anthoine Bourgeois <anthoine.bourgeois@blade-group.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Radim Krčmář <rkrcmar@redhat.com>
Cc: Anthoine Bourgeois <anthoine.bourgeois@blade-group.com>
Cc: Darren Kenny <darren.kenny@oracle.com>
Cc: Jan Kiszka <jan.kiszka@web.de>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

parent 64f7a115

arch/x86/kvm/x86.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -114,7 +114,7 @@ module_param(ignore_msrs, bool, S_IRUGO \| S_IWUSR);
	static bool __read_mostly report_ignored_msrs = true;		static bool __read_mostly report_ignored_msrs = true;
	module_param(report_ignored_msrs, bool, S_IRUGO \| S_IWUSR);		module_param(report_ignored_msrs, bool, S_IRUGO \| S_IWUSR);

	unsigned int min_timer_period_us = 500;		unsigned int min_timer_period_us = 200;
	module_param(min_timer_period_us, uint, S_IRUGO \| S_IWUSR);		module_param(min_timer_period_us, uint, S_IRUGO \| S_IWUSR);

	static bool __read_mostly kvmclock_periodic_sync = true;		static bool __read_mostly kvmclock_periodic_sync = true;