[git pull request] scheduler updates
From: Ingo Molnar
Date: Wed Aug 08 2007 - 16:30:36 EST
Linus, please pull the latest scheduler git tree from:
git://git.kernel.org/pub/scm/linux/kernel/git/mingo/linux-2.6-sched.git
the high commit count is scary, but it's all low-risk items: the main
reason is the safe and gradual elimination of a widely used 64-bit
function argument: the 64-bit "now" timestamp. About 40 of those commits
are identity transformations that prepare the real change in a safe way,
and the rest is obvious and safe as well. Besides the obvious and nice
cleanup factor, these changes are necessary for 3 reasons: firstly they
address the "there's too much 64-bit stuff in the scheduler"
observation. Secondly, it's not directly visible but these changes also
act as a correctness fix for an obscure (and minor) but
not-too-pretty-to-fix accounting bug: idle_balance() had its own
internal notion of 'now', separate from that of schedule(). Thirdly,
this debloats sched.o quite significantly:
on 32-bit (smp, nondebug), it's almost 1k less code:
text data bss dec hex filename
34869 3066 20 37955 9443 sched.o.before
33972 3066 24 37062 90c6 sched.o.after
but even on 64-bit platforms it's noticeable:
text data bss dec hex filename
28652 4162 24 32838 8046 sched.o.before
28064 4162 24 32250 7dfa sched.o.after
and that's a speedup as well, because these parameters were passed all
around the fastpath.
It was the safest to do it this way (considering that we are post -rc2
already), together in one commit these changes would have been much less
obvious to validate and apply. (It's of course all fully bisectable and
every step builds and boots fine.)
besides this elimination of the 64-bit timestamp parameter passing
between (almost all) scheduler functions, there are 8 other fixes that
are not identity transformations:
- Peter Williams reviewed the smpnice load-balancer and noticed a few
leftover items that are unnecessary now (i have re-tested
load-balancing behavior and it's all still fine)
- binary sysctl cleanup from Alexey Dobriyan
- two small accounting fixes
- reniced tasks fixes: a key calculation fix (i re-checked key nice
workloads and this has no real impact [other than improving them
slightly] - the other side of the branch fixed up the effects of this
- otherwise we'd have noticed this sooner), and two rounding
precision improvements that act against error accumulation.
- sleeper_bonus should be batched by sched_granularity and not by
stat_granularity. (this has almost no effect in practice, but a
speedup that pushes the only 64-bit division in CFS into a slowpath.)
then are are also two non-code documentation updates and minor cleanups
and uninlining.
Nevertheless, to be safe i have also done over 200 'make randconfig;
make -j bzImage' build tests:
#define UTS_VERSION "#231 SMP Wed Aug 8 21:34:24 CEST 2007"
all of which passed fine. Booted (and extensively tested) on x86-32 and
x64-32 as well, both UP and SMP - UP, 2-way to 8-way systems.
Ingo
------------------>
Alexey Dobriyan (1):
sched: remove binary sysctls from kernel.sched_domain
Josh Triplett (1):
sched: mark print_cfs_stats static
Peter Williams (2):
sched: simplify move_tasks()
sched: fix bug in balance_tasks()
Thomas Voegtle (1):
sched: mention CONFIG_SCHED_DEBUG in documentation
Ulrich Drepper (1):
sched: clean up sched_getaffinity()
Ingo Molnar (55):
sched: batch sleeper bonus
sched: reorder update_cpu_load(rq) with the ->task_tick() call
sched: uninline rq_clock()
sched: schedule() speedup
sched: clean up delta_mine
sched: delta_exec accounting fix
sched: document nice levels
sched: add [__]update_rq_clock(rq)
sched: eliminate rq_clock() use
sched: remove rq_clock()
sched: eliminate __rq_clock() use
sched: remove __rq_clock()
sched: remove 'now' use from assignments
sched: remove the 'u64 now' parameter from print_cfs_rq()
sched: remove the 'u64 now' parameter from update_curr()
sched: remove the 'u64 now' parameter from update_stats_wait_start()
sched: remove the 'u64 now' parameter from update_stats_enqueue()
sched: remove the 'u64 now' parameter from __update_stats_wait_end()
sched: remove the 'u64 now' parameter from update_stats_wait_end()
sched: remove the 'u64 now' parameter from update_stats_curr_start()
sched: remove the 'u64 now' parameter from update_stats_dequeue()
sched: remove the 'u64 now' parameter from update_stats_curr_end()
sched: remove the 'u64 now' parameter from __enqueue_sleeper()
sched: remove the 'u64 now' parameter from enqueue_sleeper()
sched: remove the 'u64 now' parameter from enqueue_entity()
sched: remove the 'u64 now' parameter from dequeue_entity()
sched: remove the 'u64 now' parameter from set_next_entity()
sched: remove the 'u64 now' parameter from pick_next_entity()
sched: remove the 'u64 now' parameter from put_prev_entity()
sched: remove the 'u64 now' parameter from update_curr_rt()
sched: remove the 'u64 now' parameter from ->enqueue_task()
sched: remove the 'u64 now' parameter from ->dequeue_task()
sched: remove the 'u64 now' parameter from ->pick_next_task()
sched: remove the 'u64 now' parameter from pick_next_task()
sched: remove the 'u64 now' parameter from ->put_prev_task()
sched: remove the 'u64 now' parameter from ->task_new()
sched: remove the 'u64 now' parameter from update_curr_load()
sched: remove the 'u64 now' parameter from inc_load()
sched: remove the 'u64 now' parameter from dec_load()
sched: remove the 'u64 now' parameter from inc_nr_running()
sched: remove the 'u64 now' parameter from dec_nr_running()
sched: remove the 'u64 now' parameter from enqueue_task()
sched: remove the 'u64 now' parameter from dequeue_task()
sched: remove the 'u64 now' parameter from deactivate_task()
sched: remove the 'u64 now' local variables
sched debug: remove the 'u64 now' parameter from print_task()/_rq()
sched: move the __update_rq_clock() call to scheduler_tick()
sched: remove __update_rq_clock() call from entity_tick()
sched: clean up set_curr_task_fair()
sched: optimize activate_task()
sched: optimize update_rq_clock() calls in the load-balancer
sched: make the multiplication table more accurate
sched: round a bit better
sched: fix update_stats_enqueue() reniced codepath
sched: refine negative nice level granularity
Documentation/sched-design-CFS.txt | 2
Documentation/sched-nice-design.txt | 108 +++++++++++
include/linux/sched.h | 20 --
kernel/sched.c | 339 ++++++++++++++++++------------------
kernel/sched_debug.c | 16 -
kernel/sched_fair.c | 212 ++++++++++------------
kernel/sched_idletask.c | 10 -
kernel/sched_rt.c | 48 +----
8 files changed, 421 insertions(+), 334 deletions(-)
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