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From: Fengguang Wu <fengguang.wu@intel.com>
To: Jan Kara <jack@suse.cz>
Cc: linux-mm@kvack.org, peterz@infradead.org
Subject: Re: [PATCH 0/2 v2] Flexible proportions for BDIs
Date: Mon, 7 May 2012 22:43:44 +0800	[thread overview]
Message-ID: <20120507144344.GA13983@localhost> (raw)
In-Reply-To: <1336084760-19534-1-git-send-email-jack@suse.cz>

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On Fri, May 04, 2012 at 12:39:18AM +0200, Jan Kara wrote:
> 
>   Hello,
> 
>   this is the second iteration of my patches for flexible proportions. Since
> previous submission, I've converted BDI proportion calculations to use flexible
> proportions so now we can test proportions in kernel. Fengguang, can you give
> them a run in your JBOD setup? You might try to tweak VM_COMPLETIONS_PERIOD_LEN
> if things are fluctuating too much... I'm not yet completely decided how to set
> that constant. Thanks!

Kara, I've got some results and it's working great. Overall performance
remains good. The default VM_COMPLETIONS_PERIOD_LEN = 0.5s is obviously
too small, so I tried increasing it to 3s and then 8s. Results for xfs
(which has most fluctuating IO completions and ditto for bdi_setpoint)
are attached. The XFS result of vanilla 3.3 is also attached. The
graphs are all for case bay/JBOD-2HDD-thresh=1000M/xfs-10dd.

Look at the gray "bdi setpoint" lines. The
VM_COMPLETIONS_PERIOD_LEN=8s kernel is able to achieve roughly the
same stable bdi_setpoint as the vanilla kernel, while being able to
adapt to the balanced bdi_setpoint much more fast (actually now the
bdi_setpoint is immediately close to the balanced value when
balance_dirty_pages() starts throttling, while the vanilla kernel
takes about 20 seconds for bdi_setpoint to grow up).

               3.4.0-rc2          3.4.0-rc2-prop8+
------------------------  ------------------------
                  195.86        +0.0%       195.87  bay/JBOD-2HDD-thresh=1000M/btrfs-10dd-1-3.4.0-rc2
                  196.68        +0.1%       196.81  bay/JBOD-2HDD-thresh=1000M/btrfs-1dd-1-3.4.0-rc2
                  187.39        -1.1%       185.28  bay/JBOD-2HDD-thresh=1000M/ext4-10dd-1-3.4.0-rc2
                  191.94        +0.7%       193.27  bay/JBOD-2HDD-thresh=1000M/ext4-1dd-1-3.4.0-rc2
                  193.01        -0.1%       192.76  bay/JBOD-2HDD-thresh=1000M/xfs-10dd-1-3.4.0-rc2
                  197.28        -0.1%       197.07  bay/JBOD-2HDD-thresh=1000M/xfs-1dd-1-3.4.0-rc2
                  197.09        -0.2%       196.74  bay/JBOD-2HDD-thresh=100M/btrfs-1dd-1-3.4.0-rc2
                  160.16        -1.2%       158.21  bay/JBOD-2HDD-thresh=100M/ext4-10dd-1-3.4.0-rc2
                  192.10        -0.1%       191.97  bay/JBOD-2HDD-thresh=100M/ext4-1dd-1-3.4.0-rc2
                  163.35        +0.3%       163.79  bay/JBOD-2HDD-thresh=100M/xfs-10dd-1-3.4.0-rc2
                  194.90        +0.0%       194.99  bay/JBOD-2HDD-thresh=100M/xfs-1dd-1-3.4.0-rc2
                  191.10        +0.2%       191.53  bay/RAID0-2HDD-thresh=1000M/btrfs-1dd-1-3.4.0-rc2
                  183.38        +2.6%       188.12  bay/RAID0-2HDD-thresh=1000M/ext4-1dd-1-3.4.0-rc2
                  196.02        -0.0%       195.99  bay/RAID0-2HDD-thresh=1000M/xfs-1dd-1-3.4.0-rc2
                  170.18        +0.3%       170.70  bay/RAID0-2HDD-thresh=100M/btrfs-1dd-1-3.4.0-rc2
                  180.79        +1.6%       183.72  bay/RAID0-2HDD-thresh=100M/ext4-1dd-1-3.4.0-rc2
                  189.00        -0.2%       188.68  bay/RAID0-2HDD-thresh=100M/xfs-1dd-1-3.4.0-rc2
                   97.57        +0.0%        97.61  bay/RAID1-2HDD-thresh=1000M/btrfs-1dd-1-3.4.0-rc2
                   96.69        +0.8%        97.50  bay/RAID1-2HDD-thresh=1000M/ext4-1dd-1-3.4.0-rc2
                   96.99        +0.9%        97.86  bay/RAID1-2HDD-thresh=1000M/xfs-1dd-1-3.4.0-rc2
                   97.53        +0.2%        97.71  bay/RAID1-2HDD-thresh=100M/btrfs-1dd-1-3.4.0-rc2
                   95.85        -0.0%        95.80  bay/RAID1-2HDD-thresh=100M/ext4-1dd-1-3.4.0-rc2
                   97.11        +0.1%        97.23  bay/RAID1-2HDD-thresh=100M/xfs-1dd-1-3.4.0-rc2
                   99.38        -0.0%        99.37  bay/thresh=1000M/btrfs-1dd-1-3.4.0-rc2
                   98.50        +0.2%        98.65  bay/thresh=1000M/ext4-1dd-1-3.4.0-rc2
                   97.54        -0.0%        97.50  bay/thresh=1000M/xfs-10dd-1-3.4.0-rc2
                   99.67        -0.1%        99.56  bay/thresh=1000M/xfs-1dd-1-3.4.0-rc2
                   99.34        -0.0%        99.33  bay/thresh=100M/btrfs-1dd-1-3.4.0-rc2
                   97.56        -0.1%        97.44  bay/thresh=100M/ext4-1dd-1-3.4.0-rc2
                   87.62        +0.2%        87.83  bay/thresh=100M/xfs-10dd-1-3.4.0-rc2
                   99.18        +0.0%        99.21  bay/thresh=100M/xfs-1dd-1-3.4.0-rc2
                   86.99        -0.8%        86.33  bay/thresh=10M/btrfs-1dd-1-3.4.0-rc2
                   91.65        -0.2%        91.42  bay/thresh=10M/ext4-1dd-1-3.4.0-rc2
                   69.54        +0.2%        69.72  bay/thresh=10M/xfs-10dd-1-3.4.0-rc2
                   91.73        +0.4%        92.10  bay/thresh=10M/xfs-1dd-1-3.4.0-rc2
                    3.31        -2.7%         3.22  bay/thresh=1M/btrfs-1dd-1-3.4.0-rc2
                   84.17        +0.7%        84.76  bay/thresh=1M/ext4-1dd-1-3.4.0-rc2
                   65.87        -2.2%        64.44  bay/thresh=1M/xfs-10dd-1-3.4.0-rc2
                   75.02        -0.6%        74.59  bay/thresh=1M/xfs-1dd-1-3.4.0-rc2
                 5109.05        +0.1%      5114.70  TOTAL write_bw

              3723146.77        +0.0%   3723782.19  TOTAL io_wkB_s
                12136.02        -0.3%     12096.63  TOTAL io_w_s
                 6246.22        +0.5%      6280.40  TOTAL io_wrqm_s
                    7.86        -5.6%         7.42  TOTAL io_rkB_s
                    2.00        -5.0%         1.90  TOTAL io_r_s
                    0.02       -38.5%         0.01  TOTAL io_rrqm_s
                35432.39        -0.0%     35417.66  TOTAL io_avgrq_sz
                 2804.24        +0.9%      2830.82  TOTAL io_avgqu_sz
                14045.59        +1.2%     14220.95  TOTAL io_await
                  150.05       +28.4%       192.65  TOTAL io_svctm
                14048.25        +1.3%     14223.99  TOTAL io_util
                   97.79        +0.4%        98.20  TOTAL cpu_user
                    0.00                      0.00  TOTAL cpu_nice
                 1150.46        -0.8%      1141.17  TOTAL cpu_system
                 1311.93        +0.5%      1319.01  TOTAL cpu_iowait
                    0.00                      0.00  TOTAL cpu_steal
                 1439.81        +0.1%      1441.63  TOTAL cpu_idle

Thanks,
Fengguang

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  parent reply	other threads:[~2012-05-07 14:45 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-05-03 22:39 [PATCH 0/2 v2] Flexible proportions for BDIs Jan Kara
2012-05-03 22:39 ` [PATCH 1/2] lib: Proportions with flexible period Jan Kara
2012-05-03 22:39 ` [PATCH 2/2] block: Convert BDI proportion calculations to flexible proportions Jan Kara
2012-05-07 14:47   ` Fengguang Wu
2012-05-07 15:21     ` Peter Zijlstra
2012-05-09 11:38       ` Jan Kara
2012-05-07 14:43 ` Fengguang Wu [this message]
2012-05-09 11:37   ` [PATCH 0/2 v2] Flexible proportions for BDIs Jan Kara
2012-05-10  7:31     ` Fengguang Wu
2012-05-11 14:51       ` Fengguang Wu
2012-05-13  3:29         ` Fengguang Wu
2012-05-14 21:28           ` Jan Kara
2012-05-15 11:12             ` Peter Zijlstra
2012-05-15 15:14               ` Jan Kara
2012-05-15 13:15             ` Fengguang Wu
2012-05-14 21:12         ` Jan Kara

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