linux/include
Frederic Weisbecker e1d8aa9f1d tracing: add a new workqueue tracer
Impact: new tracer

The workqueue tracer provides some statistical informations
about each cpu workqueue thread such as the number of the
works inserted and executed since their creation. It can help
to evaluate the amount of work each of them have to perform.
For example it can help a developer to decide whether he should
choose a per cpu workqueue instead of a singlethreaded one.

It only traces statistical informations for now but it will probably later
provide event tracing too.

Such a tracer could help too, and be improved, to help rt priority sorted
workqueue development.

To have a snapshot of the workqueues state at any time, just do

cat /debugfs/tracing/trace_stat/workqueues

Ie:

  1    125        125       reiserfs/1
  1      0          0       scsi_tgtd/1
  1      0          0       aio/1
  1      0          0       ata/1
  1    114        114       kblockd/1
  1      0          0       kintegrityd/1
  1   2147       2147       events/1

  0      0          0       kpsmoused
  0    105        105       reiserfs/0
  0      0          0       scsi_tgtd/0
  0      0          0       aio/0
  0      0          0       ata_aux
  0      0          0       ata/0
  0      0          0       cqueue
  0      0          0       kacpi_notify
  0      0          0       kacpid
  0    149        149       kblockd/0
  0      0          0       kintegrityd/0
  0   1000       1000       khelper
  0   2270       2270       events/0

Changes in V2:

_ Drop the static array based on NR_CPU and dynamically allocate the stat array
  with num_possible_cpus() and other cpu mask facilities....
_ Trace workqueue insertion at a bit lower level (insert_work instead of queue_work) to handle
  even the workqueue barriers.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Steven Rostedt <srostedt@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-14 12:11:43 +01:00
..
acpi Merge branch 'simplify_PRT' into release 2009-01-09 03:41:08 -05:00
asm-arm
asm-frv NOMMU: Make VMAs per MM as for MMU-mode linux 2009-01-08 12:04:47 +00:00
asm-generic remove linux/hardirq.h from asm-generic/local.h 2009-01-06 15:59:13 -08:00
asm-h8300
asm-m32r NOMMU: Make VMAs per MM as for MMU-mode linux 2009-01-08 12:04:47 +00:00
asm-m68k m68k: introduce asm/swab.h 2009-01-06 18:10:27 -08:00
asm-mn10300 mn10300: introduce asm/swab.h 2009-01-06 18:10:29 -08:00
crypto
drm drm: Add a debug node for vblank state. 2008-12-29 17:47:27 +10:00
keys
linux ftrace, ia64: Add macro for ftrace_caller 2009-01-14 12:11:18 +01:00
math-emu
media V4L/DVB (10141): v4l2: debugging API changed to match against driver name instead of ID. 2009-01-02 17:11:52 -02:00
mtd trivial: fix then -> than typos in comments and documentation 2009-01-06 11:28:06 +01:00
net Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/djbw/async_tx 2009-01-09 11:52:14 -08:00
pcmcia
rdma
rxrpc
scsi [SCSI] fc transport: restore missing dev_loss_tmo callback to LLDD 2009-01-06 09:43:33 -06:00
sound Merge branch 'topic/asoc' into for-linus 2009-01-06 09:48:51 +01:00
trace tracing: add a new workqueue tracer 2009-01-14 12:11:43 +01:00
video
xen xen: add xenfs to allow usermode <-> Xen interaction 2009-01-08 08:30:59 -08:00
Kbuild