linux/include
Frederic Weisbecker 76e1d9047e perf: Store active software events in a hashlist
Each time a software event triggers, we need to walk through
the entire list of events from the current cpu and task contexts
to retrieve a running perf event that matches.
We also need to check a matching perf event is actually counting.

This walk is wasteful and makes the event fast path scaling
down with a growing number of events running on the same
contexts.

To solve this, we store the running perf events in a hashlist to
get an immediate access to them against their type:event_id when
they trigger.

v2: - Fix SWEVENT_HLIST_SIZE definition (and re-learn some basic
      maths along the way)
    - Only allocate hlist for online cpus, but keep track of the
      refcount on offline possible cpus too, so that we allocate it
      if needed when it becomes online.
    - Drop the kref use as it's not adapted to our tricks anymore.

v3: - Fix bad refcount check (address instead of value). Thanks to
      Eric Dumazet who spotted this.
    - While exiting cpu, move the hlist release out of the IPI path
      to lock the hlist mutex sanely.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
2010-04-14 18:20:33 +02:00
..
acpi acpi: Support IBM SMBus CMI devices 2010-03-24 14:38:37 +01:00
asm-generic dma-mapping: pci: move pci_set_dma_mask and pci_set_consistent_dma_mask to pci-dma-compat.h 2010-03-12 15:52:42 -08:00
crypto
drm Merge branch 'master' into export-slabh 2010-04-05 11:37:28 +09:00
keys
linux perf: Store active software events in a hashlist 2010-04-14 18:20:33 +02:00
math-emu
media Merge branch 'for-next' into for-linus 2010-03-08 16:55:37 +01:00
mtd
net Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ericvh/v9fs 2010-04-05 13:42:54 -07:00
pcmcia pcmcia: use dev_pm_ops for class pcmcia_socket_class 2010-03-24 11:00:11 +01:00
rdma Merge branch 'misc' into for-next 2010-03-01 23:52:31 -08:00
rxrpc
scsi include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
sound Merge branch 'fix/asoc' into for-linus 2010-04-07 09:54:41 +02:00
trace perf: Fetch hot regs from the template caller 2010-04-04 15:23:07 +02:00
video broadsheetfb: support storing waveform 2010-03-12 15:52:34 -08:00
xen include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h 2010-03-30 22:02:32 +09:00
Kbuild