linux-toradex.git/include/linux/topology.h, branch v2.6.35.4

numa: introduce numa_mem_id()- effective local memory node id

2010-05-27T16:12:57+00:00

Introduce numa_mem_id(), based on generic percpu variable infrastructure
to track "nearest node with memory" for archs that support memoryless
nodes.

Define API in  when CONFIG_HAVE_MEMORYLESS_NODES
defined, else stubs.  Architectures will define HAVE_MEMORYLESS_NODES
if/when they support them.

Archs can override definitions of:

numa_mem_id() - returns node number of "local memory" node
set_numa_mem() - initialize [this cpus'] per cpu variable 'numa_mem'
cpu_to_mem()  - return numa_mem for specified cpu; may be used as lvalue

Generic initialization of 'numa_mem' occurs in __build_all_zonelists().
This will initialize the boot cpu at boot time, and all cpus on change of
numa_zonelist_order, or when node or memory hot-plug requires zonelist
rebuild.  Archs that support memoryless nodes will need to initialize
'numa_mem' for secondary cpus as they're brought on-line.

[akpm@linux-foundation.org: fix build]
Signed-off-by: Lee Schermerhorn 
Signed-off-by: Christoph Lameter 
Cc: Tejun Heo 
Cc: Mel Gorman 
Cc: Christoph Lameter 
Cc: Nick Piggin 
Cc: David Rientjes 
Cc: Eric Whitney 
Cc: KAMEZAWA Hiroyuki 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: "Luck, Tony" 
Cc: Pekka Enberg 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

numa: add generic percpu var numa_node_id() implementation

2010-05-27T16:12:57+00:00

Rework the generic version of the numa_node_id() function to use the new
generic percpu variable infrastructure.

Guard the new implementation with a new config option:

        CONFIG_USE_PERCPU_NUMA_NODE_ID.

Archs which support this new implemention will default this option to 'y'
when NUMA is configured.  This config option could be removed if/when all
archs switch over to the generic percpu implementation of numa_node_id().
Arch support involves:

  1) converting any existing per cpu variable implementations to use
     this implementation.  x86_64 is an instance of such an arch.
  2) archs that don't use a per cpu variable for numa_node_id() will
     need to initialize the new per cpu variable "numa_node" as cpus
     are brought on-line.  ia64 is an example.
  3) Defining USE_PERCPU_NUMA_NODE_ID in arch dependent Kconfig--e.g.,
     when NUMA is configured.  This is required because I have
     retained the old implementation by default to allow archs to
     be modified incrementally, as desired.

Subsequent patches will convert x86_64 and ia64 to use this implemenation.

Signed-off-by: Lee Schermerhorn 
Cc: Tejun Heo 
Cc: Mel Gorman 
Reviewed-by: Christoph Lameter 
Cc: Nick Piggin 
Cc: David Rientjes 
Cc: Eric Whitney 
Cc: KAMEZAWA Hiroyuki 
Cc: Ingo Molnar 
Cc: Thomas Gleixner 
Cc: "H. Peter Anvin" 
Cc: "Luck, Tony" 
Cc: Pekka Enberg 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sched: Fix vmark regression on big machines

2010-01-21T12:39:03+00:00

SD_PREFER_SIBLING is set at the CPU domain level if power saving isn't
enabled, leading to many cache misses on large machines as we traverse
looking for an idle shared cache to wake to.  Change the enabler of
select_idle_sibling() to SD_SHARE_PKG_RESOURCES, and enable same at the
sibling domain level.

Reported-by: Lin Ming 
Signed-off-by: Mike Galbraith 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <1262612696.15495.15.camel@marge.simson.net>
Signed-off-by: Ingo Molnar

sched: Disable SD_PREFER_LOCAL for MC/CPU domains

2009-10-14T13:02:34+00:00

Yanmin reported that both tbench and hackbench were significantly
hurt by trying to keep tasks local on these domains, esp on small
cache machines.

So disable it in order to promote spreading outside of the cache
domains.

Reported-by: "Zhang, Yanmin" 
Signed-off-by: Peter Zijlstra 
CC: Mike Galbraith 
LKML-Reference: <1255083400.8802.15.camel@laptop>
Signed-off-by: Ingo Molnar

cpumask: remove obsolete topology_core_siblings and topology_thread_siblings: core

2009-09-24T00:04:41+00:00

There were replaced by topology_core_cpumask and topology_thread_cpumask.

Signed-off-by: Rusty Russell

sched: Disable wakeup balancing

2009-09-16T14:44:33+00:00

Sysbench thinks SD_BALANCE_WAKE is too agressive and kbuild doesn't
really mind too much, SD_BALANCE_NEWIDLE picks up most of the
slack.

On a dual socket, quad core, dual thread nehalem system:

sysbench (--num_threads=16):

 SD_BALANCE_WAKE-: 13982 tx/s
 SD_BALANCE_WAKE+: 15688 tx/s

kbuild (-j16):

 SD_BALANCE_WAKE-: 47.648295846  seconds time elapsed   ( +-   0.312% )
 SD_BALANCE_WAKE+: 47.608607360  seconds time elapsed   ( +-   0.026% )

(same within noise)

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Add SD_PREFER_LOCAL

2009-09-16T06:42:40+00:00

And turn it on for NUMA and MC domains. This improves
locality in balancing decisions by keeping up to
capacity amount of tasks local before looking for idle
CPUs. (and twice the capacity if SD_POWERSAVINGS_BALANCE
is set.)

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Reduce forkexec_idx

2009-09-15T14:51:23+00:00

If we're looking to place a new task, we might as well find the
idlest position _now_, not 1 tick ago.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar

sched: Improve latencies and throughput

2009-09-15T14:51:16+00:00

Make the idle balancer more agressive, to improve a
x264 encoding workload provided by Jason Garrett-Glaser:

 NEXT_BUDDY NO_LB_BIAS
 encoded 600 frames, 252.82 fps, 22096.60 kb/s
 encoded 600 frames, 250.69 fps, 22096.60 kb/s
 encoded 600 frames, 245.76 fps, 22096.60 kb/s

 NO_NEXT_BUDDY LB_BIAS
 encoded 600 frames, 344.44 fps, 22096.60 kb/s
 encoded 600 frames, 346.66 fps, 22096.60 kb/s
 encoded 600 frames, 352.59 fps, 22096.60 kb/s

 NO_NEXT_BUDDY NO_LB_BIAS
 encoded 600 frames, 425.75 fps, 22096.60 kb/s
 encoded 600 frames, 425.45 fps, 22096.60 kb/s
 encoded 600 frames, 422.49 fps, 22096.60 kb/s

Peter pointed out that this is better done via newidle_idx,
not via LB_BIAS, newidle balancing should look for where
there is load _now_, not where there was load 2 ticks ago.

Worst-case latencies are improved as well as no buddies
means less vruntime spread. (as per prior lkml discussions)

This change improves kbuild-peak parallelism as well.

Reported-by: Jason Garrett-Glaser 
Signed-off-by: Mike Galbraith 
Signed-off-by: Peter Zijlstra 
LKML-Reference: <1253011667.9128.16.camel@marge.simson.net>
Signed-off-by: Ingo Molnar

sched: Fix some domain tunings

2009-09-15T14:01:08+00:00

CPU level should have WAKE_AFFINE, whereas ALLNODES is dubious.

Signed-off-by: Peter Zijlstra 
LKML-Reference: 
Signed-off-by: Ingo Molnar