From: Keir Fraser <keir.xen@gmail.com>
To: "Zhang, Yang Z" <yang.z.zhang@intel.com>,
Jan Beulich <JBeulich@suse.com>, Tim Deegan <tim@xen.org>
Cc: "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
Andres Lagar-Cavilla <andres@lagarcavilla.org>
Subject: Re: lock in vhpet
Date: Mon, 23 Apr 2012 09:22:46 +0100 [thread overview]
Message-ID: <CBBACFE6.313F8%keir.xen@gmail.com> (raw)
In-Reply-To: <A9667DDFB95DB7438FA9D7D576C3D87E0F1224@SHSMSX101.ccr.corp.intel.com>
On 23/04/2012 09:15, "Zhang, Yang Z" <yang.z.zhang@intel.com> wrote:
>>> Those data is collected when win8 guest(16 vcpus) is idle. 16 VCPUs
>>> blocked
>>> 30 seconds with 10 sec's profiling. It means 18% of cpu cycle is
>>> waiting for the p2m lock. And those data only for idle guest. The
>>> impaction is more seriously when run some workload inside guest.
>>> I noticed that this change was adding by cs 24770. And before it, we
>>> don't require the p2m lock in _get_gfn_type_access. So is this lock
>>> really necessary?
>>
>> Or shouldn't such a lock frequently taken on a read path be an rwlock
>> instead?
>>
> Right. Using rwlock would make more sense.
Interested to see if it would improve performance. My guess would be no.
-- Keir
next prev parent reply other threads:[~2012-04-23 8:22 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-17 3:26 lock in vhpet Zhang, Yang Z
2012-04-17 7:27 ` Keir Fraser
2012-04-18 0:52 ` Zhang, Yang Z
2012-04-18 7:13 ` Keir Fraser
2012-04-18 7:55 ` Zhang, Yang Z
2012-04-18 8:29 ` Keir Fraser
2012-04-18 9:14 ` Keir Fraser
2012-04-18 9:30 ` Keir Fraser
2012-04-19 5:19 ` Zhang, Yang Z
2012-04-19 8:27 ` Tim Deegan
2012-04-19 8:47 ` Keir Fraser
2012-04-23 7:36 ` Zhang, Yang Z
2012-04-23 7:43 ` Jan Beulich
2012-04-23 8:15 ` Zhang, Yang Z
2012-04-23 8:22 ` Keir Fraser [this message]
2012-04-23 9:14 ` Tim Deegan
2012-04-23 15:26 ` Andres Lagar-Cavilla
2012-04-24 9:15 ` Tim Deegan
2012-04-24 13:28 ` Andres Lagar-Cavilla
2012-04-23 17:18 ` Andres Lagar-Cavilla
2012-04-24 8:58 ` Zhang, Yang Z
2012-04-24 9:16 ` Tim Deegan
2012-04-25 0:27 ` Zhang, Yang Z
2012-04-25 1:40 ` Andres Lagar-Cavilla
2012-04-25 1:48 ` Zhang, Yang Z
2012-04-25 2:31 ` Andres Lagar-Cavilla
2012-04-25 2:36 ` Zhang, Yang Z
2012-04-25 2:42 ` Andres Lagar-Cavilla
2012-04-25 3:12 ` Zhang, Yang Z
2012-04-25 3:34 ` Andres Lagar-Cavilla
2012-04-25 5:18 ` Zhang, Yang Z
2012-04-25 8:07 ` Jan Beulich
2012-04-26 21:25 ` Tim Deegan
2012-04-27 0:46 ` Zhang, Yang Z
2012-04-27 0:51 ` Andres Lagar-Cavilla
2012-04-27 1:24 ` Zhang, Yang Z
2012-04-27 8:36 ` Zhang, Yang Z
2012-04-27 3:02 ` Andres Lagar-Cavilla
2012-04-27 9:26 ` Tim Deegan
2012-04-27 14:17 ` Andres Lagar-Cavilla
2012-04-27 21:08 ` Andres Lagar-Cavilla
2012-05-16 11:36 ` Zhang, Yang Z
2012-05-16 12:36 ` Tim Deegan
2012-05-17 10:57 ` Tim Deegan
2012-05-28 6:54 ` Zhang, Yang Z
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