unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
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Chris Mason ac6e60ee40 mutex: adaptive spinnning, performance tweaks 
Spin more agressively. This is less fair but also markedly faster.

The numbers:

 * dbench 50 (higher is better):
  spin        1282MB/s
  v10         548MB/s
  v10 no wait 1868MB/s

 * 4k creates (numbers in files/second higher is better):
  spin        avg 200.60 median 193.20 std 19.71 high 305.93 low 186.82
  v10         avg 180.94 median 175.28 std 13.91 high 229.31 low 168.73
  v10 no wait avg 232.18 median 222.38 std 22.91 high 314.66 low 209.12

 * File stats (numbers in seconds, lower is better):
  spin        2.27s
  v10         5.1s
  v10 no wait 1.6s

( The source changes are smaller than they look, I just moved the
  need_resched checks in __mutex_lock_common after the cmpxchg. )

Signed-off-by: Chris Mason <chris.mason@oracle.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-01-14 19:03:54 +01:00
..
irq async: Asynchronous function calls to speed up kernel boot 2009-01-07 08:45:46 -08:00
power Merge branch 'linus' into release 2009-01-09 03:39:43 -05:00
time Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial 2009-01-07 11:31:52 -08:00
trace Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/rric/oprofile 2009-01-09 12:43:06 -08:00
.gitignore
acct.c CRED: Wrap task credential accesses in the core kernel 2008-11-14 10:39:12 +11:00
async.c async: fix __lowest_in_progress() 2009-01-12 16:39:58 -08:00
audit.c [PATCH] fix broken timestamps in AVC generated by kernel threads 2008-12-09 02:27:41 -05:00
audit.h fixing audit rule ordering mess, part 1 2009-01-04 15:14:41 -05:00
audit_tree.c audit: validate comparison operations, store them in sane form 2009-01-04 15:14:42 -05:00
auditfilter.c audit: validate comparison operations, store them in sane form 2009-01-04 15:14:42 -05:00
auditsc.c make sure that filterkey of task,always rules is reported 2009-01-04 15:14:42 -05:00
backtracetest.c
bounds.c
capability.c Merge branch 'next' into for-linus 2009-01-07 09:58:22 +11:00
cgroup.c cgroups: add css_tryget() 2009-01-08 08:31:10 -08:00
cgroup_debug.c
cgroup_freezer.c freezer_cg: disable writing freezer.state of root cgroup 2008-11-12 17:17:16 -08:00
compat.c Allow times and time system calls to return small negative values 2009-01-06 15:59:13 -08:00
configs.c
cpu.c stop_machine/cpu hotplug: fix disable_nonboot_cpus 2009-01-07 11:36:14 -08:00
cpuset.c cpuset: remove remaining pointers to cpumask_t 2009-01-08 08:31:11 -08:00
cred-internals.h CRED: Inaugurate COW credentials 2008-11-14 10:39:23 +11:00
cred.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 2009-01-09 13:59:25 -08:00
delayacct.c schedstat: consolidate per-task cpu runtime stats 2008-12-18 13:54:01 +01:00
dma-coherent.c dma-coherent: catch oversized requests to dma_alloc_from_coherent() 2009-01-06 15:59:31 -08:00
dma.c
exec_domain.c
exit.c mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting 2009-01-06 15:59:09 -08:00
extable.c Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-30 16:10:19 -08:00
fork.c Merge git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-2.6-nommu 2009-01-09 14:00:58 -08:00
freezer.c
futex.c Merge branches 'core/futexes', 'core/locking', 'core/rcu' and 'linus' into core/urgent 2009-01-06 09:32:11 +01:00
futex_compat.c CRED: Use RCU to access another task's creds and to release a task's own creds 2008-11-14 10:39:19 +11:00
hrtimer.c hrtimer: splitout peek ahead functionality, fix 2009-01-05 14:11:10 +01:00
itimer.c
kallsyms.c allow stripping of generated symbols under CONFIG_KALLSYMS_ALL 2008-12-19 22:47:10 +01:00
Kconfig.freezer
Kconfig.hz
Kconfig.preempt rcu: provide RCU options on non-preempt architectures too 2008-12-25 09:31:28 +01:00
kexec.c cpumask: prepare for iterators to only go to nr_cpu_ids/nr_cpumask_bits.: core 2009-01-01 10:12:15 +10:30
kfifo.c
kgdb.c
kmod.c kmod: fix varargs kernel-doc 2009-01-06 15:59:27 -08:00
kprobes.c kprobes: support probing module __init function 2009-01-06 15:59:21 -08:00
ksysfs.c kernel/ksysfs.c:fix dependence on CONFIG_NET 2009-01-06 10:44:31 -08:00
kthread.c tracepoints: add DECLARE_TRACE() and DEFINE_TRACE() 2008-11-16 09:01:36 +01:00
latencytop.c KSYM_SYMBOL_LEN fixes 2008-12-10 08:01:54 -08:00
lockdep.c Merge branch 'core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-30 16:10:19 -08:00
lockdep_internals.h
lockdep_proc.c
Makefile smp_call_function_single(): be slightly less stupid 2009-01-11 03:41:58 +01:00
marker.c markers/tracpoints: fix non-modular build 2008-11-16 09:52:03 +01:00
module.c async: Asynchronous function calls to speed up kernel boot 2009-01-07 08:45:46 -08:00
mutex-debug.c mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex-debug.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
mutex.c mutex: adaptive spinnning, performance tweaks 2009-01-14 19:03:54 +01:00
mutex.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
notifier.c Merge commit 'v2.6.28-rc6' into core/debug 2008-11-26 08:22:50 +01:00
ns_cgroup.c ns_cgroup: remove unused spinlock 2009-01-08 08:31:02 -08:00
nsproxy.c User namespaces: set of cleanups (v2) 2008-11-24 18:57:41 -05:00
panic.c oops: increment the oops UUID every time we oops 2009-01-06 15:59:12 -08:00
params.c
pid.c pid: generalize task_active_pid_ns 2009-01-08 08:31:12 -08:00
pid_namespace.c
pm_qos_params.c
posix-cpu-timers.c Merge commit 'v2.6.28' into core/core 2008-12-25 13:51:46 +01:00
posix-timers.c Merge branches 'timers/clocksource', 'timers/hpet', 'timers/hrtimers', 'timers/nohz', 'timers/ntp', 'timers/posixtimers' and 'timers/rtc' into timers/core 2008-12-25 18:02:25 +01:00
printk.c trivial: printk: fix indentation of new_text_line declaration 2009-01-06 11:28:06 +01:00
profile.c profile: don't include <asm/ptrace.h> twice. 2009-01-06 15:59:14 -08:00
ptrace.c Merge branch 'tracing-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-28 12:21:10 -08:00
rcuclassic.c cpumask: convert RCU implementations, fix 2009-01-03 18:59:25 +01:00
rcupdate.c rcu: eliminate synchronize_rcu_xxx macro 2009-01-05 10:18:08 +01:00
rcupreempt.c rcu: eliminate synchronize_rcu_xxx macro 2009-01-05 10:18:08 +01:00
rcupreempt_trace.c "Tree RCU": scalable classic RCU implementation 2008-12-18 21:56:04 +01:00
rcutorture.c rcu: fix bug in rcutorture system-shutdown code 2009-01-07 23:36:25 +01:00
rcutree.c rcu: make treercu safe for suspend and resume 2009-01-05 10:12:33 +01:00
rcutree_trace.c "Tree RCU": scalable classic RCU implementation 2008-12-18 21:56:04 +01:00
relay.c relayfs: fix infinite loop with splice() 2008-12-10 08:01:52 -08:00
res_counter.c memcg: memory cgroup resource counters for hierarchy 2009-01-08 08:31:05 -08:00
resource.c resource: allow MMIO exclusivity for device drivers 2009-01-07 11:12:32 -08:00
rtmutex-debug.c
rtmutex-debug.h
rtmutex-tester.c
rtmutex.c
rtmutex.h
rtmutex_common.h
rwsem.c
sched.c mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
sched_clock.c sched_clock: prevent scd->clock from moving backwards, take #2 2008-12-31 09:53:21 +01:00
sched_cpupri.c sched: fix section mismatch 2009-01-06 11:07:15 +01:00
sched_cpupri.h sched: convert struct cpupri_vec cpumask_var_t. 2008-11-24 17:52:22 +01:00
sched_debug.c sched: partly revert "sched debug: remove NULL checking in print_cfs_rt_rq()" 2009-01-11 02:40:32 +01:00
sched_fair.c generic swap(): sched: remove local swap() macro 2009-01-08 08:31:15 -08:00
sched_features.h mutex: implement adaptive spinning 2009-01-14 18:09:02 +01:00
sched_idletask.c
sched_rt.c sched: put back some stack hog changes that were undone in kernel/sched.c 2009-01-03 19:00:09 +01:00
sched_stats.h Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumask into merge-rr-cpumask 2009-01-03 18:53:31 +01:00
seccomp.c
semaphore.c
signal.c SEND_SIG_NOINFO: set si_pid to tgid instead of pid 2009-01-06 15:59:29 -08:00
smp.c cpumask: prepare for iterators to only go to nr_cpu_ids/nr_cpumask_bits.: core 2009-01-01 10:12:15 +10:30
softirq.c Merge branch 'cpus4096-for-linus-3' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-03 12:04:39 -08:00
softlockup.c cpumask: convert rest of files in kernel/ 2009-01-01 10:12:28 +10:30
spinlock.c
srcu.c
stacktrace.c stacktrace: provide save_stack_trace_tsk() weak alias 2008-12-25 11:44:43 +01:00
stop_machine.c stop_machine: introduce stop_machine_create/destroy. 2009-01-05 08:40:14 +10:30
sys.c Merge branch 'sched-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2009-01-06 17:10:33 -08:00
sys_ni.c reintroduce accept4 2008-11-19 18:49:57 -08:00
sysctl.c NOMMU: Make mmap allocation page trimming behaviour configurable. 2009-01-08 12:04:47 +00:00
sysctl_check.c
taskstats.c cpumask: convert rest of files in kernel/ 2009-01-01 10:12:28 +10:30
test_kprobes.c kprobes: add tests for register_kprobes 2009-01-06 15:59:20 -08:00
time.c Allow times and time system calls to return small negative values 2009-01-06 15:59:13 -08:00
timeconst.pl
timer.c [PATCH] idle cputime accounting 2008-12-31 15:11:46 +01:00
tracepoint.c markers/tracpoints: fix non-modular build 2008-11-16 09:52:03 +01:00
tsacct.c mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting 2009-01-06 15:59:09 -08:00
uid16.c CRED: Wrap current->cred and a few other accessors 2008-11-14 10:39:18 +11:00
up.c smp_call_function_single(): be slightly less stupid, fix #2 2009-01-12 16:04:37 +01:00
user.c Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip 2008-12-28 12:27:58 -08:00
user_namespace.c User namespaces: set of cleanups (v2) 2008-11-24 18:57:41 -05:00
utsname.c
utsname_sysctl.c
wait.c
workqueue.c cpumask: convert kernel/workqueue.c 2009-01-01 10:12:25 +10:30