From: Tom Yan <tom.ty89@gmail.com>
To: LVM general discussion and development <linux-lvm@redhat.com>
Cc: Zdenek Kabelac <zkabelac@redhat.com>,
Martin Wilck <martin.wilck@suse.com>,
"heming.zhao@suse.com" <heming.zhao@suse.com>
Subject: Re: [linux-lvm] Discussion: performance issue on event activation mode
Date: Sat, 3 Jul 2021 05:31:09 +0800 [thread overview]
Message-ID: <CAGnHSE=GJ7UFMDPFqkrp4Y6604BccRQn-a_KA4iTeuOe0_hwUQ@mail.gmail.com> (raw)
In-Reply-To: <20210702210903.GA15057@redhat.com>
On Sat, 3 Jul 2021 at 05:17, David Teigland <teigland@redhat.com> wrote:
>
> On Sun, Jun 06, 2021 at 02:15:23PM +0800, heming.zhao@suse.com wrote:
> > dev_cache_scan //order: O(n^2)
> > + _insert_dirs //O(n)
> > | if obtain_device_list_from_udev() true
> > | _insert_udev_dir //O(n)
> > |
> > + dev_cache_index_devs //O(n)
>
> I've been running some experiments and trying some patches to improve
> this. By setting obtain_device_list_from_udev=0, and using the attached
> patch to disable dev_cache_index_devs, the pvscan is much better.
>
> systemctl status lvm2-pvscan appears to show that the pvscan command
> itself runs for only 2-4 seconds, while the service as a whole takes
> around 15 seconds. See the 16 sec gap below from the end of pvscan
> to the systemd Started message. If that's accurate, the remaining delay
> would lie outside lvm.
Not necessarily. It could be pvscan stalling for 16s after printing
the "now active" message for some reason before exiting (with 0).
>
> Jul 02 15:27:57 localhost.localdomain systemd[1]: Starting LVM event activation on device 253:1710...
> Jul 02 15:28:00 localhost.localdomain lvm[65620]: pvscan[65620] PV /dev/mapper/mpathalz online, VG 1ed02c7d-0019-43c4-91b5-f220f3521ba9 is complete.
> Jul 02 15:28:00 localhost.localdomain lvm[65620]: pvscan[65620] VG 1ed02c7d-0019-43c4-91b5-f220f3521ba9 run autoactivation.
> Jul 02 15:28:00 localhost.localdomain lvm[65620]: 1 logical volume(s) in volume group "1ed02c7d-0019-43c4-91b5-f220f3521ba9" now active
> Jul 02 15:28:16 localhost.localdomain systemd[1]: Started LVM event activation on device 253:1710.
>
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://listman.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
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prev parent reply other threads:[~2021-07-02 21:31 UTC|newest]
Thread overview: 86+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-06-06 6:15 [linux-lvm] Discussion: performance issue on event activation mode heming.zhao
2021-06-06 16:35 ` Roger Heflin
2021-06-07 10:27 ` Martin Wilck
2021-06-07 15:30 ` heming.zhao
2021-06-07 15:45 ` Martin Wilck
2021-06-07 20:52 ` Roger Heflin
2021-06-07 21:30 ` David Teigland
2021-06-08 8:26 ` Martin Wilck
2021-06-08 15:39 ` David Teigland
2021-06-08 15:47 ` Martin Wilck
2021-06-08 16:02 ` Zdenek Kabelac
2021-06-08 16:05 ` Martin Wilck
2021-06-08 16:03 ` David Teigland
2021-06-08 16:07 ` Martin Wilck
2021-06-15 17:03 ` David Teigland
2021-06-15 18:21 ` Zdenek Kabelac
2021-06-16 16:18 ` heming.zhao
2021-06-16 16:38 ` David Teigland
2021-06-17 3:46 ` heming.zhao
2021-06-17 15:27 ` David Teigland
2021-06-08 16:49 ` heming.zhao
2021-06-08 16:18 ` heming.zhao
2021-06-09 4:01 ` heming.zhao
2021-06-09 5:37 ` Heming Zhao
2021-06-09 18:59 ` David Teigland
2021-06-10 17:23 ` heming.zhao
2021-06-07 15:48 ` Martin Wilck
2021-06-07 16:31 ` Zdenek Kabelac
2021-06-07 21:48 ` David Teigland
2021-06-08 12:29 ` Peter Rajnoha
2021-06-08 13:23 ` Martin Wilck
2021-06-08 13:41 ` Peter Rajnoha
2021-06-08 13:46 ` Zdenek Kabelac
2021-06-08 13:56 ` Peter Rajnoha
2021-06-08 14:23 ` Zdenek Kabelac
2021-06-08 14:48 ` Martin Wilck
2021-06-08 15:19 ` Peter Rajnoha
2021-06-08 15:39 ` Martin Wilck
2021-09-09 19:44 ` David Teigland
2021-09-10 17:38 ` Martin Wilck
2021-09-12 16:51 ` heming.zhao
2021-09-27 10:00 ` Peter Rajnoha
2021-09-27 15:38 ` David Teigland
2021-09-28 6:34 ` Martin Wilck
2021-09-28 14:42 ` David Teigland
2021-09-28 15:16 ` Martin Wilck
2021-09-28 15:31 ` Martin Wilck
2021-09-28 15:56 ` David Teigland
2021-09-28 18:03 ` Benjamin Marzinski
2021-09-28 17:42 ` Benjamin Marzinski
2021-09-28 19:15 ` Martin Wilck
2021-09-29 22:06 ` Peter Rajnoha
2021-09-30 7:51 ` Martin Wilck
2021-09-30 8:07 ` heming.zhao
2021-09-30 9:31 ` Martin Wilck
2021-09-30 11:41 ` Peter Rajnoha
2021-09-30 15:32 ` heming.zhao
2021-10-01 7:41 ` Martin Wilck
2021-10-01 8:08 ` Peter Rajnoha
2021-09-30 11:29 ` Peter Rajnoha
2021-09-30 16:04 ` David Teigland
2021-09-30 14:41 ` Benjamin Marzinski
2021-10-01 7:42 ` Martin Wilck
2021-09-29 21:53 ` Peter Rajnoha
2021-09-30 7:45 ` Martin Wilck
2021-09-29 21:39 ` Peter Rajnoha
2021-09-30 7:22 ` Martin Wilck
2021-09-30 14:26 ` David Teigland
2021-09-30 15:55 ` David Teigland
2021-10-01 8:00 ` Peter Rajnoha
2021-10-18 6:24 ` Martin Wilck
2021-10-18 15:04 ` David Teigland
2021-10-18 16:56 ` heming.zhao
2021-10-18 21:51 ` Zdenek Kabelac
2021-10-19 17:18 ` David Teigland
2021-10-20 14:40 ` Martin Wilck
2021-10-20 14:50 ` David Teigland
2021-10-20 14:54 ` Martin Wilck
2021-10-20 15:12 ` David Teigland
2021-06-07 16:40 ` David Teigland
2021-07-02 21:09 ` David Teigland
2021-07-02 21:22 ` Martin Wilck
2021-07-02 22:02 ` David Teigland
2021-07-03 11:49 ` heming.zhao
2021-07-08 10:10 ` Tom Yan
2021-07-02 21:31 ` Tom Yan [this message]
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