From: Bruce Guenter <bruce@untroubled.org>
To: linux-btrfs <linux-btrfs@vger.kernel.org>
Subject: Re: Slow snapshot deletion
Date: Thu, 4 Aug 2011 10:35:36 -0600 [thread overview]
Message-ID: <20110804163536.GA25185@untroubled.org> (raw)
In-Reply-To: <1311886250-sup-5126@shiny>
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On Thu, Jul 28, 2011 at 04:51:24PM -0400, Chris Mason wrote:
> Sorry, hit send too soon. Here is the latencytop patch, after you
> recompile run latencytop -c for a few minutes. Send the output here.
>
> http://oss.oracle.com/~mason/latencytop.patch
Ok, I ran it for more than a few minutes. Early on (shortly after boot), the output shows this for a long time:
=============== Mon Aug 1 21:09:30 2011
Globals: Cause Maximum Percentage
Process details:
Process ksoftirqd/0 (3) Total: 3.9 msec
[run_ksoftirqd] 3.9 msec 100.0 %
run_ksoftirqd kthread kernel_thread_helper
Process kworker/1:1 (983) Total: 31.2 msec
. 3.9 msec 100.0 %
worker_thread kthread kernel_thread_helper
Process sshd (3948) Total: 3.9 msec
Waiting for event (select) 3.9 msec 100.0 %
poll_schedule_timeout do_select core_sys_select sys_select
system_call_fastpath
Process btrfs-cleaner (4345) Total: 2433.6 msec
[sleep_on_page] 31.3 msec 100.0 %
sleep_on_page wait_on_page_bit read_extent_buffer_pages
btree_read_extent_buffer_pages read_tree_block
read_block_for_search btrfs_search_slot
lookup_inline_extent_backref __btrfs_free_extent
run_clustered_refs btrfs_run_delayed_refs __btrfs_end_transaction
Process btrfs-transacti (4346) Total: 2437.5 msec
[sleep_on_page] 27.3 msec 100.0 %
sleep_on_page wait_on_page_bit read_extent_buffer_pages
btree_read_extent_buffer_pages read_tree_block
read_block_for_search btrfs_search_slot
lookup_inline_extent_backref __btrfs_free_extent
run_clustered_refs btrfs_run_delayed_refs btrfs_commit_transaction
This repeats identically (all numbers and backtrace is very stable) for
a long time. Much later, I see this:
=============== Tue Aug 2 13:46:29 2011
Globals: Cause Maximum Percentage
Process details:
Process btrfs-submit-0 (4332) Total: 199.2 msec
Creating block layer request 58.6 msec 100.0 %
get_request_wait __make_request generic_make_request
submit_bio run_scheduled_bios pending_bios_fn worker_loop
kthread kernel_thread_helper
Process btrfs-cleaner (4345) Total: 3.9 msec
Creating block layer request 3.9 msec 100.0 %
get_request_wait __make_request generic_make_request
submit_bio btrfs_map_bio btree_submit_bio_hook submit_one_bio
read_extent_buffer_pages readahead_tree_block reada_walk_down
do_walk_down walk_down_tree
Process btrfs-endio-met (4700) Total: 35.2 msec
[worker_loop] 3.9 msec 100.0 %
worker_loop kthread kernel_thread_helper
Process kworker/1:2 (26315) Total: 50.8 msec
. 3.9 msec 100.0 %
worker_thread kthread kernel_thread_helper
[...snip...]
=============== Thu Aug 4 12:34:08 2011
Globals: Cause Maximum Percentage
Process details:
Process btrfs-submit-0 (4332) Total: 199.2 msec
Creating block layer request 58.6 msec 100.0 %
get_request_wait __make_request generic_make_request
submit_bio run_scheduled_bios pending_bios_fn worker_loop
kthread kernel_thread_helper
Process btrfs-cleaner (4345) Total: 3.9 msec
Creating block layer request 3.9 msec 100.0 %
get_request_wait __make_request generic_make_request
submit_bio btrfs_map_bio btree_submit_bio_hook submit_one_bio
read_extent_buffer_pages readahead_tree_block reada_walk_down
do_walk_down walk_down_tree
Process btrfs-endio-met (4700) Total: 35.2 msec
[worker_loop] 3.9 msec 100.0 %
worker_loop kthread kernel_thread_helper
--
Bruce Guenter <bruce@untroubled.org> http://untroubled.org/
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next prev parent reply other threads:[~2011-08-04 16:35 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-07-28 20:04 Slow snapshot deletion Bruce Guenter
2011-07-28 20:28 ` Chris Mason
2011-07-28 20:51 ` Chris Mason
2011-08-04 16:35 ` Bruce Guenter [this message]
2011-08-11 15:04 ` Bruce Guenter
2011-08-12 0:40 ` Simon Kirby
2011-08-12 18:21 ` Bruce Guenter
2011-08-12 18:26 ` Simon Kirby
2011-08-01 22:26 ` Bruce Guenter
2011-08-01 22:41 ` cwillu
2011-08-01 22:59 ` Bruce Guenter
2011-08-02 0:29 ` Chris Mason
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