linux-toradex.git/include/linux/topology.h, branch v2.6.27.31

cpu topology: always define CPU topology information

2008-06-13T08:09:46+00:00

This can result in an empty topology directory in sysfs, and requires
in-kernel users to protect all uses with #ifdef - see
.

The documentation of CPU topology specifies what the defaults should be if
only partial information is available from the hardware.  So we can
provide these defaults as a fallback.

This patch:

- Adds default definitions of the 4 topology macros to 
- Changes drivers/base/topology.c to use the topology macros unconditionally
  and to cope with definitions that aren't lvalues
- Updates documentation accordingly

[ From: Andrew Morton 
  - fold now-duplicated code
  - fix layout
]

Signed-off-by: Ben Hutchings 
Cc: Vegard Nossum 
Cc: Nick Piggin 
Cc: Chandra Seetharaman 
Cc: Suresh Siddha 
Cc: Mike Travis 
Cc: Christoph Lameter 
Cc: John Hawkes 
Cc: Zhang, Yanmin 
Signed-off-by: Andrew Morton 
Signed-off-by: Ingo Molnar

sched: re-tune NUMA topologies

2008-05-29T12:46:30+00:00

improve the sysbench ramp-up phase and its peak throughput on
a 16way NUMA box, by turning on WAKE_AFFINE:

             tip/sched   tip/sched+wake-affine
-------------------------------------------------
    1:             700              830    +15.65%
    2:            1465             1391    -5.28%
    4:            3017             3105    +2.81%
    8:            5100             6021    +15.30%
   16:           10725            10745    +0.19%
   32:           10135            10150    +0.16%
   64:            9338             9240    -1.06%
  128:            8599             8252    -4.21%
  256:            8475             8144    -4.07%
-------------------------------------------------
  SUM:           57558            57882    +0.56%

this change also improves lat_ctx from 6.69 usecs to 1.11 usec:

  $ ./lat_ctx -s 0 2
  "size=0k ovr=1.19
  2 1.11

  $ ./lat_ctx -s 0 2
  "size=0k ovr=1.22
  2 6.69

in sysbench it's an overall win with some weakness at the lots-of-clients
side. That happens because we now under-balance this workload
a bit. To counter that effect, turn on NEWIDLE:

              wake-idle          wake-idle+newidle
 -------------------------------------------------
     1:             830              834    +0.43%
     2:            1391             1401    +0.65%
     4:            3105             3091    -0.43%
     8:            6021             6046    +0.42%
    16:           10745            10736    -0.08%
    32:           10150            10206    +0.55%
    64:            9240             9533    +3.08%
   128:            8252             8355    +1.24%
   256:            8144             8384    +2.87%
 -------------------------------------------------
   SUM:           57882            58591    +1.21%

as a bonus this not only improves the many-clients case but
also improves the (more important) rampup phase.

sysbench is a workload that quickly breaks down if the
scheduler over-balances, so since it showed an improvement
under NEWIDLE this change is definitely good.

cpumask: reduce stack usage in SD_x_INIT initializers

2008-04-19T17:44:59+00:00

  * Remove empty cpumask_t (and all non-zero/non-null) variables
    in SD_*_INIT macros.  Use memset(0) to clear.  Also, don't
    inline the initializer functions to save on stack space in
    build_sched_domains().

  * Merge change to include/linux/topology.h that uses the new
    node_to_cpumask_ptr function in the nr_cpus_node macro into
    this patch.

Depends on:
	[mm-patch]: asm-generic-add-node_to_cpumask_ptr-macro.patch
	[sched-devel]: sched: add new set_cpus_allowed_ptr function

Cc: H. Peter Anvin 
Signed-off-by: Mike Travis 
Signed-off-by: Ingo Molnar

sched: add arch_update_cpu_topology hook.

2008-03-21T15:43:48+00:00

Will be called each time the scheduling domains are rebuild.
Needed for architectures that don't have a static cpu topology.

Signed-off-by: Heiko Carstens 
Signed-off-by: Martin Schwidefsky 
Signed-off-by: Ingo Molnar

sched: tune multi-core idle balancing

2008-03-19T03:27:53+00:00

WAKE_IDLE is too agressive on multi-core CPUs with the new
wake-affine code, keep it on for SMT/HT balancing alone
(where there's no cache affinity at all between logical CPUs).

Signed-off-by: Ingo Molnar

sched: whitespace cleanups in topology.h

2008-01-25T20:08:20+00:00

whitespace cleanups in topology.h.

Signed-off-by: Ingo Molnar

sched: reactivate fork balancing

2008-01-25T20:08:20+00:00

reactivate fork balancing.

Signed-off-by: Ingo Molnar

sched: enable wake-idle on CONFIG_SCHED_MC=y

2007-10-15T15:00:19+00:00

most multicore CPUs today have shared L2 caches, so tune things so
that the spreading amongst cores is more aggressive.

Signed-off-by: Ingo Molnar

sched: reintroduce topology.h tunings

2007-10-15T15:00:19+00:00

reintroduce the 2.6.22 topology.h tunings again - they result in
slightly better balancing.

Signed-off-by: Ingo Molnar

[PATCH] sched: remove cache_hot_time

2007-08-02T15:41:40+00:00

remove the last unused remains of cache_hot_time.

Signed-off-by: Ingo Molnar