* What is swapper, and why it is causing so many wakeups?
@ 2009-06-24 14:16 Corrado Zoccolo
2009-06-25 11:20 ` Robin Holt
0 siblings, 1 reply; 2+ messages in thread
From: Corrado Zoccolo @ 2009-06-24 14:16 UTC (permalink / raw)
To: Linux-Kernel, Arjan van de Ven
[-- Attachment #1: Type: text/plain, Size: 5499 bytes --]
Hi,
my /proc/timer_stats shows a lot of activity due to 'swapper'.
It is currently the main cause of wakeups on my netbook, an acer
aspire one with Atom N270 cpu.
The funny thing is that I have no swap partition, so I don't think
swapper should have so much work to do.
Is there a way to reduce its activity?
Timer Stats Version: v0.2
Sample period: 298.025 s
23207, 0 swapper hrtimer_start_range_ns (tick_sched_timer)
23806, 0 swapper hrtimer_start_range_ns (tick_sched_timer)
651, 2615 lxterminal hrtimer_start_range_ns (hrtimer_wakeup)
3275D, 1520 S50cpufreq cpufreq_governor_dbs (delayed_work_timer_fn)
3373D, 1520 S50cpufreq cpufreq_governor_dbs (delayed_work_timer_fn)
60, 0 swapper page_writeback_init (wb_timer_fn)
60, 2582 xscreensaver hrtimer_start_range_ns (hrtimer_wakeup)
21, 2139 X hrtimer_start (it_real_fn)
1684, 0 swapper hrtimer_start (tick_sched_timer)
279, 2139 X queue_delayed_work (delayed_work_timer_fn)
297, 2585 lxpanel hrtimer_start_range_ns (hrtimer_wakeup)
298, 2272 ifplugd hrtimer_start_range_ns (hrtimer_wakeup)
149, 2156 ifplugd hrtimer_start_range_ns (hrtimer_wakeup)
37, 2139 X hrtimer_start_range_ns (hrtimer_wakeup)
30, 2221 ip ath5k_start (ath5k_calibrate)
1040, 0 swapper hrtimer_start (tick_sched_timer)
38, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
50, 2156 ifplugd __netdev_watchdog_up (dev_watchdog)
75, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
284D, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
273D, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
149, 2545 net_applet hrtimer_start_range_ns (hrtimer_wakeup)
149, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
149, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
60, 1 init hrtimer_start_range_ns (hrtimer_wakeup)
24, 1321 btrfs-transacti schedule_timeout (process_timeout)
137, 1 swapper enqueue_task_rt (sched_rt_period_timer)
74, 2594 menu-cached hrtimer_start_range_ns (hrtimer_wakeup)
48, 2269 wpa_supplicant hrtimer_start_range_ns (hrtimer_wakeup)
1296, 484 phy0 queue_delayed_work (delayed_work_timer_fn)
30, 1 swapper sta_info_start (sta_info_cleanup)
2, 0 swapper neigh_add_timer (neigh_timer_handler)
3, 1276 mount start_this_handle (commit_timeout)
1, 2998 iwgetid do_acct_process (acct_timeout)
5, 1 swapper queue_delayed_work (delayed_work_timer_fn)
2, 479 async/1 scsi_request_fn (blk_rq_timed_out_timer)
5, 1708 crond hrtimer_start_range_ns (hrtimer_wakeup)
10, 1564 syslogd hrtimer_start (it_real_fn)
9, 1756 hald hrtimer_start_range_ns (hrtimer_wakeup)
1, 1 swapper inet_init (inet_frag_secret_rebuild)
1, 1 swapper flow_cache_init (flow_cache_new_hashrnd)
1, 1 swapper ipv6_frag_init (inet_frag_secret_rebuild)
3, 0 swapper addrconf_verify (addrconf_verify)
1, 1 swapper queue_delayed_work (delayed_work_timer_fn)
1, 3017 modprobe do_acct_process (acct_timeout)
1, 252 ksuspend_usbd schedule_timeout (process_timeout)
1, 252 ksuspend_usbd schedule_timeout (process_timeout)
1, 252 ksuspend_usbd schedule_timeout (process_timeout)
8, 258 khubd schedule_timeout (process_timeout)
110, 0 swapper ehci_work (ehci_watchdog)
2, 258 khubd schedule_timeout (process_timeout)
2, 258 khubd schedule_timeout (process_timeout)
1, 3044 usb-stor-scan schedule_timeout (process_timeout)
1, 3058 scsi_scan_2 scsi_request_fn (blk_rq_timed_out_timer)
4, 3043 usb-storage schedule_timeout (process_timeout)
1, 3043 usb-storage schedule_timeout (process_timeout)
1, 3043 usb-storage schedule_timeout (process_timeout)
1, 258 khubd schedule_timeout (process_timeout)
1, 3070 usb-stor-scan schedule_timeout (process_timeout)
1, 3086 async/0 schedule_timeout (process_timeout)
1, 3084 scsi_scan_3 scsi_request_fn (blk_rq_timed_out_timer)
1, 3042 pam_console_app do_acct_process (acct_timeout)
2, 1 swapper inet_initpeers (peer_check_expire)
1, 3144 iwgetid do_acct_process (acct_timeout)
1, 1312 btrfs-endio-met schedule_timeout (process_timeout)
1, 3151 modprobe do_acct_process (acct_timeout)
9, 2139 X vt_ioctl (kd_nosound)
1, 3176 modprobe do_acct_process (acct_timeout)
10, 3235 iwlist hrtimer_start_range_ns (hrtimer_wakeup)
8, 2615 lxterminal hrtimer_start_range_ns (hrtimer_wakeup)
1, 3003 less do_acct_process (acct_timeout)
61320 total events, 205.994 events/sec
--
__________________________________________________________________________
dott. Corrado Zoccolo mailto:czoccolo@gmail.com
PhD - Department of Computer Science - University of Pisa, Italy
--------------------------------------------------------------------------
[-- Attachment #2: timer_stats --]
[-- Type: application/octet-stream, Size: 4895 bytes --]
Timer Stats Version: v0.2
Sample period: 298.025 s
23207, 0 swapper hrtimer_start_range_ns (tick_sched_timer)
23806, 0 swapper hrtimer_start_range_ns (tick_sched_timer)
651, 2615 lxterminal hrtimer_start_range_ns (hrtimer_wakeup)
3275D, 1520 S50cpufreq cpufreq_governor_dbs (delayed_work_timer_fn)
3373D, 1520 S50cpufreq cpufreq_governor_dbs (delayed_work_timer_fn)
60, 0 swapper page_writeback_init (wb_timer_fn)
60, 2582 xscreensaver hrtimer_start_range_ns (hrtimer_wakeup)
21, 2139 X hrtimer_start (it_real_fn)
1684, 0 swapper hrtimer_start (tick_sched_timer)
279, 2139 X queue_delayed_work (delayed_work_timer_fn)
297, 2585 lxpanel hrtimer_start_range_ns (hrtimer_wakeup)
298, 2272 ifplugd hrtimer_start_range_ns (hrtimer_wakeup)
149, 2156 ifplugd hrtimer_start_range_ns (hrtimer_wakeup)
37, 2139 X hrtimer_start_range_ns (hrtimer_wakeup)
30, 2221 ip ath5k_start (ath5k_calibrate)
1040, 0 swapper hrtimer_start (tick_sched_timer)
38, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
50, 2156 ifplugd __netdev_watchdog_up (dev_watchdog)
75, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
284D, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
273D, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
149, 2545 net_applet hrtimer_start_range_ns (hrtimer_wakeup)
149, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
149, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
60, 1 init hrtimer_start_range_ns (hrtimer_wakeup)
24, 1321 btrfs-transacti schedule_timeout (process_timeout)
137, 1 swapper enqueue_task_rt (sched_rt_period_timer)
74, 2594 menu-cached hrtimer_start_range_ns (hrtimer_wakeup)
48, 2269 wpa_supplicant hrtimer_start_range_ns (hrtimer_wakeup)
1296, 484 phy0 queue_delayed_work (delayed_work_timer_fn)
30, 1 swapper sta_info_start (sta_info_cleanup)
2, 0 swapper neigh_add_timer (neigh_timer_handler)
3, 1276 mount start_this_handle (commit_timeout)
1, 2998 iwgetid do_acct_process (acct_timeout)
5, 1 swapper queue_delayed_work (delayed_work_timer_fn)
2, 479 async/1 scsi_request_fn (blk_rq_timed_out_timer)
5, 1708 crond hrtimer_start_range_ns (hrtimer_wakeup)
10, 1564 syslogd hrtimer_start (it_real_fn)
9, 1756 hald hrtimer_start_range_ns (hrtimer_wakeup)
1, 1 swapper inet_init (inet_frag_secret_rebuild)
1, 1 swapper flow_cache_init (flow_cache_new_hashrnd)
1, 1 swapper ipv6_frag_init (inet_frag_secret_rebuild)
3, 0 swapper addrconf_verify (addrconf_verify)
1, 1 swapper queue_delayed_work (delayed_work_timer_fn)
1, 3017 modprobe do_acct_process (acct_timeout)
1, 252 ksuspend_usbd schedule_timeout (process_timeout)
1, 252 ksuspend_usbd schedule_timeout (process_timeout)
1, 252 ksuspend_usbd schedule_timeout (process_timeout)
8, 258 khubd schedule_timeout (process_timeout)
110, 0 swapper ehci_work (ehci_watchdog)
2, 258 khubd schedule_timeout (process_timeout)
2, 258 khubd schedule_timeout (process_timeout)
1, 3044 usb-stor-scan schedule_timeout (process_timeout)
1, 3058 scsi_scan_2 scsi_request_fn (blk_rq_timed_out_timer)
4, 3043 usb-storage schedule_timeout (process_timeout)
1, 3043 usb-storage schedule_timeout (process_timeout)
1, 3043 usb-storage schedule_timeout (process_timeout)
1, 258 khubd schedule_timeout (process_timeout)
1, 3070 usb-stor-scan schedule_timeout (process_timeout)
1, 3086 async/0 schedule_timeout (process_timeout)
1, 3084 scsi_scan_3 scsi_request_fn (blk_rq_timed_out_timer)
1, 3042 pam_console_app do_acct_process (acct_timeout)
2, 1 swapper inet_initpeers (peer_check_expire)
1, 3144 iwgetid do_acct_process (acct_timeout)
1, 1312 btrfs-endio-met schedule_timeout (process_timeout)
1, 3151 modprobe do_acct_process (acct_timeout)
9, 2139 X vt_ioctl (kd_nosound)
1, 3176 modprobe do_acct_process (acct_timeout)
10, 3235 iwlist hrtimer_start_range_ns (hrtimer_wakeup)
8, 2615 lxterminal hrtimer_start_range_ns (hrtimer_wakeup)
1, 3003 less do_acct_process (acct_timeout)
61320 total events, 205.994 events/sec
^ permalink raw reply [flat|nested] 2+ messages in thread* Re: What is swapper, and why it is causing so many wakeups?
2009-06-24 14:16 What is swapper, and why it is causing so many wakeups? Corrado Zoccolo
@ 2009-06-25 11:20 ` Robin Holt
0 siblings, 0 replies; 2+ messages in thread
From: Robin Holt @ 2009-06-25 11:20 UTC (permalink / raw)
To: Corrado Zoccolo; +Cc: Linux-Kernel, Arjan van de Ven
Search include/linux/init_task.h for swapper. It defines the task
that each processor executes when their runqueue is empty. All you
are seeing is task-wise idle cpu that is servicing interrupts, etc and
completing work.
Good Luck,
Robin
On Wed, Jun 24, 2009 at 04:16:19PM +0200, Corrado Zoccolo wrote:
> Hi,
> my /proc/timer_stats shows a lot of activity due to 'swapper'.
> It is currently the main cause of wakeups on my netbook, an acer
> aspire one with Atom N270 cpu.
> The funny thing is that I have no swap partition, so I don't think
> swapper should have so much work to do.
> Is there a way to reduce its activity?
>
> Timer Stats Version: v0.2
> Sample period: 298.025 s
> 23207, 0 swapper hrtimer_start_range_ns (tick_sched_timer)
> 23806, 0 swapper hrtimer_start_range_ns (tick_sched_timer)
> 651, 2615 lxterminal hrtimer_start_range_ns (hrtimer_wakeup)
> 3275D, 1520 S50cpufreq cpufreq_governor_dbs (delayed_work_timer_fn)
> 3373D, 1520 S50cpufreq cpufreq_governor_dbs (delayed_work_timer_fn)
> 60, 0 swapper page_writeback_init (wb_timer_fn)
> 60, 2582 xscreensaver hrtimer_start_range_ns (hrtimer_wakeup)
> 21, 2139 X hrtimer_start (it_real_fn)
> 1684, 0 swapper hrtimer_start (tick_sched_timer)
> 279, 2139 X queue_delayed_work (delayed_work_timer_fn)
> 297, 2585 lxpanel hrtimer_start_range_ns (hrtimer_wakeup)
> 298, 2272 ifplugd hrtimer_start_range_ns (hrtimer_wakeup)
> 149, 2156 ifplugd hrtimer_start_range_ns (hrtimer_wakeup)
> 37, 2139 X hrtimer_start_range_ns (hrtimer_wakeup)
> 30, 2221 ip ath5k_start (ath5k_calibrate)
> 1040, 0 swapper hrtimer_start (tick_sched_timer)
> 38, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
> 50, 2156 ifplugd __netdev_watchdog_up (dev_watchdog)
> 75, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
> 284D, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
> 273D, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
> 149, 2545 net_applet hrtimer_start_range_ns (hrtimer_wakeup)
> 149, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
> 149, 1 swapper schedule_delayed_work_on (delayed_work_timer_fn)
> 60, 1 init hrtimer_start_range_ns (hrtimer_wakeup)
> 24, 1321 btrfs-transacti schedule_timeout (process_timeout)
> 137, 1 swapper enqueue_task_rt (sched_rt_period_timer)
> 74, 2594 menu-cached hrtimer_start_range_ns (hrtimer_wakeup)
> 48, 2269 wpa_supplicant hrtimer_start_range_ns (hrtimer_wakeup)
> 1296, 484 phy0 queue_delayed_work (delayed_work_timer_fn)
> 30, 1 swapper sta_info_start (sta_info_cleanup)
> 2, 0 swapper neigh_add_timer (neigh_timer_handler)
> 3, 1276 mount start_this_handle (commit_timeout)
> 1, 2998 iwgetid do_acct_process (acct_timeout)
> 5, 1 swapper queue_delayed_work (delayed_work_timer_fn)
> 2, 479 async/1 scsi_request_fn (blk_rq_timed_out_timer)
> 5, 1708 crond hrtimer_start_range_ns (hrtimer_wakeup)
> 10, 1564 syslogd hrtimer_start (it_real_fn)
> 9, 1756 hald hrtimer_start_range_ns (hrtimer_wakeup)
> 1, 1 swapper inet_init (inet_frag_secret_rebuild)
> 1, 1 swapper flow_cache_init (flow_cache_new_hashrnd)
> 1, 1 swapper ipv6_frag_init (inet_frag_secret_rebuild)
> 3, 0 swapper addrconf_verify (addrconf_verify)
> 1, 1 swapper queue_delayed_work (delayed_work_timer_fn)
> 1, 3017 modprobe do_acct_process (acct_timeout)
> 1, 252 ksuspend_usbd schedule_timeout (process_timeout)
> 1, 252 ksuspend_usbd schedule_timeout (process_timeout)
> 1, 252 ksuspend_usbd schedule_timeout (process_timeout)
> 8, 258 khubd schedule_timeout (process_timeout)
> 110, 0 swapper ehci_work (ehci_watchdog)
> 2, 258 khubd schedule_timeout (process_timeout)
> 2, 258 khubd schedule_timeout (process_timeout)
> 1, 3044 usb-stor-scan schedule_timeout (process_timeout)
> 1, 3058 scsi_scan_2 scsi_request_fn (blk_rq_timed_out_timer)
> 4, 3043 usb-storage schedule_timeout (process_timeout)
> 1, 3043 usb-storage schedule_timeout (process_timeout)
> 1, 3043 usb-storage schedule_timeout (process_timeout)
> 1, 258 khubd schedule_timeout (process_timeout)
> 1, 3070 usb-stor-scan schedule_timeout (process_timeout)
> 1, 3086 async/0 schedule_timeout (process_timeout)
> 1, 3084 scsi_scan_3 scsi_request_fn (blk_rq_timed_out_timer)
> 1, 3042 pam_console_app do_acct_process (acct_timeout)
> 2, 1 swapper inet_initpeers (peer_check_expire)
> 1, 3144 iwgetid do_acct_process (acct_timeout)
> 1, 1312 btrfs-endio-met schedule_timeout (process_timeout)
> 1, 3151 modprobe do_acct_process (acct_timeout)
> 9, 2139 X vt_ioctl (kd_nosound)
> 1, 3176 modprobe do_acct_process (acct_timeout)
> 10, 3235 iwlist hrtimer_start_range_ns (hrtimer_wakeup)
> 8, 2615 lxterminal hrtimer_start_range_ns (hrtimer_wakeup)
> 1, 3003 less do_acct_process (acct_timeout)
> 61320 total events, 205.994 events/sec
>
> --
> __________________________________________________________________________
>
> dott. Corrado Zoccolo mailto:czoccolo@gmail.com
> PhD - Department of Computer Science - University of Pisa, Italy
> --------------------------------------------------------------------------
^ permalink raw reply [flat|nested] 2+ messages in thread
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