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From: Anand Jain <Anand.Jain@oracle.com>
To: dsterba@suse.cz, linux-btrfs@vger.kernel.org,
	guihc.fnst@cn.fujitsu.com, sandeen@redhat.com
Subject: Re: [PATCH 1/5] btrfs-progs: scan /proc/partitions not all of /dev with "-d"
Date: Mon, 06 Oct 2014 17:31:39 +0800	[thread overview]
Message-ID: <5432617B.8050301@oracle.com> (raw)
In-Reply-To: <20140923170002.GX9715@twin.jikos.cz>



  I am running some tests with larger disks pool (48 disks).
  With that the performance of the various scan methods are as below..

----
scanning BTRFS_SCAN_LBLKID
real    0m0.330s
user    0m0.005s
sys     0m0.026s

scanning BTRFS_SCAN_DEV
real    0m0.010s
user    0m0.002s
sys     0m0.005s

scanning BTRFS_SCAN_PROC
real    0m0.010s
user    0m0.002s
sys     0m0.005s
-----

  This is the time taken to scan 48disks one time by various methods
  we have/had - but our progs do this scan 30times for btrfs fi show.
  yep 30times as show below.. I am working to fix it.

-------
                                 Function: time(us)    count  avg(us)
::
                          get_device_info:     1034       27       38
                     pretty_size_snprintf:     1218      124        9
                    btrfs_scan_one_device:     1790      186        9
                     btrfs_read_dev_super:     1956      116       16
                                 cmd_show:    15418      335       46
                        btrfs_scan_lblkid:   148477       30     4949
-------

  IMO we should still stick to LBLKID scan.
  Just a thought - any idea if its better to provide a compile time
  fallback scan switch, just in case if something fails with lblkid. ?


Thanks, Anand


On 09/24/14 01:00, David Sterba wrote:
> Hi,
>
> all 5 patches will be in the next integration. I haven't tested them
> yet, seems it's a bit more important to make a more stable devel base
> for more updates you might want to send.
> --
> To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>

  reply	other threads:[~2014-10-06  9:31 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-09-13  1:21 [PATCH 1/5] btrfs-progs: scan /proc/partitions not all of /dev with "-d" Anand Jain
2014-09-13  1:21 ` [PATCH 2/5] btrfs-progs: don't fall back to recursive /dev scan Anand Jain
2014-09-13  1:21 ` [PATCH 3/5] btrfs-progs: remove BTRFS_SCAN_DEV and btrfs_scan_one_dir Anand Jain
2014-09-13  1:21 ` [PATCH 4/5] btrfs-progs: remove BTRFS_SCAN_PROC scan method Anand Jain
2014-10-07  0:08   ` [PATCH] btrfs-progs: btrfs_scan_block_devices is unused function delete it Anand Jain
2014-10-22 11:10     ` Anand Jain
2015-05-05 16:54     ` David Sterba
2014-09-13  1:21 ` [PATCH 5/5] btrfs-progs: remove scan_for_btrfs() Anand Jain
2014-09-23 17:00 ` [PATCH 1/5] btrfs-progs: scan /proc/partitions not all of /dev with "-d" David Sterba
2014-10-06  9:31   ` Anand Jain [this message]
2014-10-23 13:12     ` Anand Jain

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