From: Igor Druzhinin <igor.druzhinin@citrix.com>
To: <xen-devel@lists.xenproject.org>
Cc: andrew.cooper3@citrix.com,
Igor Druzhinin <igor.druzhinin@citrix.com>,
wl@xen.org, jbeulich@suse.com, roger.pau@citrix.com
Subject: [Xen-devel] [PATCH 0/2] vTSC performance improvements
Date: Fri, 13 Dec 2019 22:48:00 +0000 [thread overview]
Message-ID: <1576277282-6590-1-git-send-email-igor.druzhinin@citrix.com> (raw)
In our PV shim testing we've noticed constant lockups of guests with high
number of vCPUs assigned that usually happening when there is another guest
running on the same host. Reproing the problem manually and dumping shim
state immediately showed that most of the vCPUs are locked on vtsc_lock.
As PV shim guest always gets emulated TSC due to L1 Xen itself not being
provided with ITSC the ideal solution would be to try dropping the lock
entirely.
Igor Druzhinin (2):
x86/time: drop vtsc_{kern,user}count debug counters
x86/time: update vtsc_last with cmpxchg and drop vtsc_lock
xen/arch/x86/domain.c | 1 -
xen/arch/x86/hvm/hvm.c | 32 ++------------------------------
xen/arch/x86/time.c | 28 ++++++----------------------
xen/include/asm-x86/domain.h | 5 -----
4 files changed, 8 insertions(+), 58 deletions(-)
--
2.7.4
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next reply other threads:[~2019-12-13 22:48 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-13 22:48 Igor Druzhinin [this message]
2019-12-13 22:48 ` [Xen-devel] [PATCH 1/2] x86/time: drop vtsc_{kern, user}count debug counters Igor Druzhinin
2019-12-16 9:47 ` Roger Pau Monné
2019-12-16 14:24 ` Andrew Cooper
2019-12-13 22:48 ` [Xen-devel] [PATCH 2/2] x86/time: update vtsc_last with cmpxchg and drop vtsc_lock Igor Druzhinin
2019-12-16 10:00 ` Roger Pau Monné
2019-12-16 11:21 ` Jan Beulich
2019-12-16 12:30 ` Roger Pau Monné
2019-12-16 12:45 ` Jan Beulich
2019-12-16 12:55 ` Roger Pau Monné
2019-12-16 12:53 ` Igor Druzhinin
2019-12-16 12:57 ` Roger Pau Monné
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