From: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
To: habanero@linux.vnet.ibm.com
Cc: Avi Kivity <avi@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Rik van Riel <riel@redhat.com>, "H. Peter Anvin" <hpa@zytor.com>,
Ingo Molnar <mingo@redhat.com>,
Marcelo Tosatti <mtosatti@redhat.com>,
Srikar <srikar@linux.vnet.ibm.com>,
"Nikunj A. Dadhania" <nikunj@linux.vnet.ibm.com>,
KVM <kvm@vger.kernel.org>, Jiannan Ouyang <ouyang@cs.pitt.edu>,
chegu vinod <chegu_vinod@hp.com>,
LKML <linux-kernel@vger.kernel.org>,
Srivatsa Vaddagiri <srivatsa.vaddagiri@gmail.com>,
Gleb Natapov <gleb@redhat.com>, Andrew Jones <drjones@redhat.com>
Subject: Re: [PATCH RFC 1/2] kvm: Handle undercommitted guest case in PLE handler
Date: Mon, 15 Oct 2012 17:40:20 +0530 [thread overview]
Message-ID: <507BFD2C.3010808@linux.vnet.ibm.com> (raw)
In-Reply-To: <1349897783.22418.15.camel@oc2024037011.ibm.com>
On 10/11/2012 01:06 AM, Andrew Theurer wrote:
> On Wed, 2012-10-10 at 23:24 +0530, Raghavendra K T wrote:
>> On 10/10/2012 08:29 AM, Andrew Theurer wrote:
>>> On Wed, 2012-10-10 at 00:21 +0530, Raghavendra K T wrote:
>>>> * Avi Kivity <avi@redhat.com> [2012-10-04 17:00:28]:
>>>>
>>>>> On 10/04/2012 03:07 PM, Peter Zijlstra wrote:
>>>>>> On Thu, 2012-10-04 at 14:41 +0200, Avi Kivity wrote:
>>>>>>>
[...]
>>> A big concern I have (if this is 1x overcommit) for ebizzy is that it
>>> has just terrible scalability to begin with. I do not think we should
>>> try to optimize such a bad workload.
>>>
>>
>> I think my way of running dbench has some flaw, so I went to ebizzy.
>> Could you let me know how you generally run dbench?
>
> I mount a tmpfs and then specify that mount for dbench to run on. This
> eliminates all IO. I use a 300 second run time and number of threads is
> equal to number of vcpus. All of the VMs of course need to have a
> synchronized start.
>
> I would also make sure you are using a recent kernel for dbench, where
> the dcache scalability is much improved. Without any lock-holder
> preemption, the time in spin_lock should be very low:
>
>
>> 21.54% 78016 dbench [kernel.kallsyms] [k] copy_user_generic_unrolled
>> 3.51% 12723 dbench libc-2.12.so [.] __strchr_sse42
>> 2.81% 10176 dbench dbench [.] child_run
>> 2.54% 9203 dbench [kernel.kallsyms] [k] _raw_spin_lock
>> 2.33% 8423 dbench dbench [.] next_token
>> 2.02% 7335 dbench [kernel.kallsyms] [k] __d_lookup_rcu
>> 1.89% 6850 dbench libc-2.12.so [.] __strstr_sse42
>> 1.53% 5537 dbench libc-2.12.so [.] __memset_sse2
>> 1.47% 5337 dbench [kernel.kallsyms] [k] link_path_walk
>> 1.40% 5084 dbench [kernel.kallsyms] [k] kmem_cache_alloc
>> 1.38% 5009 dbench libc-2.12.so [.] memmove
>> 1.24% 4496 dbench libc-2.12.so [.] vfprintf
>> 1.15% 4169 dbench [kernel.kallsyms] [k] __audit_syscall_exit
>
Hi Andrew,
I ran the test with dbench with tmpfs. I do not see any improvements in
dbench for 16k ple window.
So it seems apart from ebizzy no workload benefited by that. and I
agree that, it may not be good to optimize for ebizzy.
I shall drop changing to 16k default window and continue with other
original patch series. Need to experiment with latest kernel.
(PS: Thanks for pointing towards, perf in latest kernel. It works fine.)
Results:
dbench run for 120 sec 30 sec warmup 8 iterations using tmpfs
base = 3.6.0-rc5 with ple handler optimization patch.
x => base + ple_window = 4k
+ => base + ple_window = 16k
* => base + ple_gap = 0
dbench 1x overcommit case
=========================
N Min Max Median Avg Stddev
x 8 5322.5 5519.05 5482.71 5461.0962 63.522276
+ 8 5255.45 5530.55 5496.94 5455.2137 93.070363
* 8 5350.85 5477.81 5408.065 5418.4338 44.762697
dbench 2x overcommit case
==========================
N Min Max Median Avg Stddev
x 8 3054.32 3194.47 3137.33 3132.625 54.491615
+ 8 3040.8 3148.87 3088.615 3088.1887 32.862336
* 8 3031.51 3171.99 3083.6 3097.4612 50.526977
next prev parent reply other threads:[~2012-10-15 12:14 UTC|newest]
Thread overview: 126+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-21 11:59 [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios in PLE handler Raghavendra K T
2012-09-21 12:00 ` [PATCH RFC 1/2] kvm: Handle undercommitted guest case " Raghavendra K T
2012-09-21 13:02 ` Rik van Riel
2012-09-21 17:24 ` Raghavendra K T
2012-09-24 15:41 ` Avi Kivity
2012-09-24 16:06 ` Avi Kivity
2012-09-24 16:14 ` Peter Zijlstra
2012-09-24 16:25 ` Avi Kivity
2012-09-25 8:09 ` Raghavendra K T
2012-09-25 8:54 ` Avi Kivity
2012-09-25 13:49 ` Raghavendra K T
2012-09-27 7:44 ` Gleb Natapov
2012-09-27 8:59 ` Avi Kivity
2012-09-27 9:11 ` Gleb Natapov
2012-09-27 9:33 ` Avi Kivity
2012-09-27 9:58 ` Gleb Natapov
2012-09-27 10:04 ` Avi Kivity
2012-09-27 10:08 ` Gleb Natapov
2012-09-27 10:15 ` Avi Kivity
[not found] ` <CAJocwcf+8u84_yDC-PK0Yni93YSTWzYvr69nq6b3pNv1MwVJzQ@mail.gmail.com>
2012-09-27 8:50 ` Avi Kivity
2012-09-27 11:26 ` Raghavendra K T
2012-09-27 12:06 ` Avi Kivity
2012-09-28 18:18 ` Konrad Rzeszutek Wilk
2012-09-30 8:16 ` Avi Kivity
[not found] ` <CAJocwcc19F+PtsQ5okGMvYeVnkEigpZRpwWY9JgeRPFqfcVoXA@mail.gmail.com>
2012-09-28 6:16 ` Raghavendra K T
2012-09-30 8:18 ` Avi Kivity
2012-09-30 11:07 ` Gleb Natapov
2012-09-30 11:13 ` Avi Kivity
2012-10-03 14:17 ` Raghavendra K T
2012-10-03 14:56 ` Avi Kivity
2012-10-04 7:29 ` Gleb Natapov
2012-10-05 8:36 ` Raghavendra K T
2012-10-07 9:51 ` Avi Kivity
2012-09-25 7:36 ` Raghavendra K T
2012-09-25 8:12 ` Avi Kivity
2012-09-25 14:21 ` Takuya Yoshikawa
2012-09-27 8:43 ` Avi Kivity
2012-10-03 12:22 ` Raghavendra K T
2012-10-03 17:05 ` Avi Kivity
2012-10-04 10:49 ` Raghavendra K T
2012-10-04 12:41 ` Avi Kivity
2012-10-04 13:07 ` Peter Zijlstra
2012-10-04 15:00 ` Avi Kivity
2012-10-09 18:51 ` Raghavendra K T
2012-10-10 2:59 ` Andrew Theurer
2012-10-10 17:54 ` Raghavendra K T
2012-10-10 18:03 ` David Ahern
2012-10-10 18:14 ` Raghavendra K T
2012-10-10 19:36 ` Andrew Theurer
2012-10-15 12:10 ` Raghavendra K T [this message]
2012-10-15 14:34 ` Andrew Theurer
2012-10-19 8:30 ` Raghavendra K T
2012-10-19 13:31 ` Andrew Theurer
2012-10-10 14:24 ` Andrew Theurer
2012-10-10 17:43 ` Raghavendra K T
2012-10-10 19:27 ` Andrew Theurer
2012-10-11 17:13 ` Raghavendra K T
2012-10-11 10:39 ` Nikunj A Dadhania
2012-10-18 12:39 ` Avi Kivity
2012-10-19 8:19 ` Raghavendra K T
2012-10-04 14:41 ` Andrew Theurer
2012-10-05 9:06 ` Raghavendra K T
2012-10-05 9:02 ` Raghavendra K T
2012-09-24 11:33 ` Peter Zijlstra
2012-09-24 11:40 ` Raghavendra K T
2012-09-21 12:00 ` [PATCH RFC 2/2] kvm: Be courteous to other VMs in overcommitted scenario " Raghavendra K T
2012-09-21 13:22 ` Rik van Riel
2012-09-21 13:46 ` Takuya Yoshikawa
2012-09-21 13:52 ` Rik van Riel
2012-09-21 17:45 ` Raghavendra K T
2012-09-24 13:43 ` Takuya Yoshikawa
2012-09-24 15:26 ` Avi Kivity
2012-09-24 15:34 ` Peter Zijlstra
2012-09-24 15:43 ` Avi Kivity
2012-09-24 15:52 ` Peter Zijlstra
2012-09-24 15:58 ` Avi Kivity
2012-09-24 16:05 ` Peter Zijlstra
2012-09-24 16:10 ` Avi Kivity
2012-09-24 16:13 ` Peter Zijlstra
2012-09-24 16:21 ` Avi Kivity
2012-09-25 10:11 ` Avi Kivity
2012-09-21 13:18 ` [PATCH RFC 0/2] kvm: Improving undercommit,overcommit scenarios " Chegu Vinod
2012-09-21 17:36 ` Raghavendra K T
2012-09-24 8:42 ` Dor Laor
2012-09-24 12:02 ` Raghavendra K T
2012-09-25 15:00 ` Dor Laor
2012-09-26 12:27 ` Konrad Rzeszutek Wilk
2012-09-27 10:07 ` Raghavendra K T
2012-09-27 9:49 ` Raghavendra K T
2012-09-27 10:28 ` Andrew Jones
2012-09-27 10:44 ` Avi Kivity
2012-09-27 11:31 ` Raghavendra K T
2012-09-27 10:33 ` Dor Laor
2012-09-24 11:34 ` Peter Zijlstra
2012-09-24 11:52 ` Raghavendra K T
2012-09-24 12:36 ` Peter Zijlstra
2012-09-24 13:29 ` Raghavendra K T
2012-09-24 13:54 ` Peter Zijlstra
2012-09-24 14:16 ` Raghavendra K T
2012-09-25 13:40 ` Raghavendra K T
2012-09-27 8:36 ` Avi Kivity
2012-09-27 11:23 ` Raghavendra K T
2012-09-27 12:03 ` Avi Kivity
2012-09-27 12:25 ` Andrew Theurer
2012-09-28 5:38 ` Raghavendra K T
2012-09-28 5:45 ` H. Peter Anvin
2012-09-28 6:03 ` Raghavendra K T
2012-09-28 8:38 ` Peter Zijlstra
2012-09-28 11:40 ` Andrew Theurer
2012-09-28 14:11 ` Raghavendra K T
2012-09-28 14:13 ` Peter Zijlstra
2012-09-30 8:24 ` Avi Kivity
2012-10-03 14:29 ` Raghavendra K T
2012-10-03 17:25 ` Avi Kivity
2012-10-04 10:56 ` Raghavendra K T
2012-10-04 12:44 ` Avi Kivity
2012-10-05 9:04 ` Raghavendra K T
2012-09-24 15:51 ` Avi Kivity
2012-09-24 16:03 ` Peter Zijlstra
2012-09-24 16:20 ` Avi Kivity
2012-09-26 13:20 ` Andrew Jones
2012-09-26 13:26 ` Peter Zijlstra
2012-09-26 13:39 ` Andrew Jones
2012-09-26 13:45 ` Peter Zijlstra
2012-09-26 12:57 ` Andrew Jones
2012-09-27 10:21 ` Raghavendra K T
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