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SubjectRe: 2.6.25-rc3-mm1 - PROFILE_LIKELY redux..
On Wed, 05 Mar 2008 17:26:25 -0500
Valdis.Kletnieks@vt.edu wrote:

> On Wed, 05 Mar 2008 10:02:21 PST, Andrew Morton said:
>
> > at the top, so it'll be something else. Perhaps a `likely' snuck in via an
> > inline in a header file. It would be better to add a #define DONT_DO_THAT
> > at the top of arch/x86/kernel/vsyscall_64.c and
> > arch/x86/vdso/vclock_gettime.c, then use that to defeat likely-profiling.
> >
> > arch/x86/kernel/vsyscall_64.c | 11 ++---------
> > arch/x86/vdso/vclock_gettime.c | 11 ++---------
> > include/linux/compiler.h | 3 ++-
> > 3 files changed, 6 insertions(+), 19 deletions(-)
>
> Confirming that this patch works and my system goes multi-user cleanly.

Thanks.

> Actual numbers after about 10 minutes of uptime:
>
> % wc -l /proc/likely_prof
> 2635 /proc/likely_prof
> % grep '^[^ ]' /proc/likely_prof
> Likely Profiling Results
> [+- ] Type | # True | # False | Function:Filename@Line
> +unlikely | 1| 0 in_dev_get()@:include/linux/inetdevice.h@185
> +unlikely | 513| 0 dst_input()@:include/net/dst.h@254
> -likely | 0| 148 ip6_mc_input()@:net/ipv6/ip6_input.c@271
> -likely | 0| 1 sock_error()@:include/net/sock.h@1211
> -likely | 851| 1219 tcp_transmit_skb()@:net/ipv4/tcp_output.c@493
> +unlikely | 1| 0 signal_pending()@:include/linux/sched.h@1927
> -likely | 0| 1172946 audit_syscall_entry()@:kernel/auditsc.c@1522
> +unlikely | 1172716| 0 syscall_trace_enter()@:arch/x86/kernel/ptrace.c@1556
> -likely | 0| 1173020 audit_syscall_exit()@:kernel/auditsc.c@1551
> +unlikely | 1172831| 0 syscall_trace_leave()@:arch/x86/kernel/ptrace.c@1573
> -likely | 0| 1272 audit_alloc()@:kernel/auditsc.c@841
> +unlikely | 3| 0 icmp_unreach()@:net/ipv4/icmp.c@773
> +unlikely | 2| 1 nf_ct_attach()@:net/netfilter/core.c@230
> -likely | 0| 2 dst_gc_task()@:net/core/dst.c@82
> +unlikely | 143| 61 fput_light()@:include/linux/file.h@77
> +unlikely | 892| 424 _read_unlock_irqrestore()@:kernel/spinlock.c@375
> +unlikely | 28| 0 sched_move_task()@:kernel/sched.c@7835
> +unlikely | 28| 0 sched_move_task()@:kernel/sched.c@7828
> +unlikely | 108| 0 verify_export_symbols()@:kernel/module.c@1401
> +unlikely | 313| 0 verify_export_symbols()@:kernel/module.c@1393
> +unlikely | 14| 0 ll_front_merge_fn()@:block/blk-merge.c@347
> -likely | 17| 1150 audit_free()@:kernel/auditsc.c@1428
> -likely | 17| 1174290 audit_get_context()@:kernel/auditsc.c@711
> +unlikely | 33| 0 inotify_find_update_watch()@:fs/inotify.c@591
> +unlikely | 4360| 775 kill_pid_info()@:kernel/signal.c@1065
> +unlikely | 7239| 2767 next_pidmap()@:kernel/pid.c@194
> +unlikely | 42009| 33683 copy_pte_range()@:mm/memory.c@510
> -likely | 0| 1 qh_completions()@:drivers/usb/host/ehci-q.c@368
> +unlikely | 19934| 0 ll_back_merge_fn()@:block/blk-merge.c@309
> -likely | 927| 2323 load_elf_binary()@:fs/binfmt_elf.c@896
> +unlikely | 2435| 875 pmd_alloc()@:include/linux/mm.h@862
> +unlikely | 13| 12 psmouse_interrupt()@:drivers/input/mouse/psmouse-base.c@296
> +unlikely | 70| 25 psmouse_interrupt()@:drivers/input/mouse/psmouse-base.c@292
> -likely | 20| 80 qh_completions()@:drivers/usb/host/ehci-q.c@415
> -likely | 0| 30 qh_completions()@:drivers/usb/host/ehci-q.c@319
> -likely | 5| 14 submit_async()@:drivers/usb/host/ehci-q.c@975
> +unlikely | 19| 2 qh_append_tds()@:drivers/usb/host/ehci-q.c@876
> -likely | 6| 15 atapi_drain_needed()@:drivers/ata/libata-scsi.c@846
> +unlikely | 27395| 18153 add_timer_randomness()@:drivers/char/random.c@628
> +unlikely | 34665| 19948 bio_phys_segments()@:fs/bio.c@226
> -likely | 347| 678 clocksource_adjust()@:kernel/time/timekeeping.c@418
> -likely | 1| 4 __ata_qc_from_tag()@:include/linux/libata.h@1319
> -likely | 0| 15 __cancel_work_timer()@:kernel/workqueue.c@490
> +unlikely | 15638| 1127 queue_delayed_work_on()@:kernel/workqueue.c@233
> +unlikely | 2| 0 srcu_notifier_chain_register()@:kernel/notifier.c@419
> +unlikely | 6502| 2429 queue_work()@:kernel/workqueue.c@171
> +unlikely | 9| 2 blocking_notifier_chain_register()@:kernel/notifier.c@212
> +unlikely | 13631| 0 pre_schedule_rt()@:kernel/sched_rt.c@961
> +unlikely | 591400| 443725 __update_curr()@:kernel/sched_fair.c@313
> +unlikely | 233625| 205658 __switch_to()@:arch/x86/kernel/process_64.c@656
> +unlikely | 313057| 126225 __switch_to()@:arch/x86/kernel/process_64.c@641
> +unlikely | 313053| 126225 __switch_to()@:arch/x86/kernel/process_64.c@637
> +unlikely | 467383| 0 sched_info_switch()@:kernel/sched_stats.h@230
> +unlikely | 188448| 13628 pick_next_task_rt()@:kernel/sched_rt.c@522
> +unlikely | 240619| 0 sched_info_queued()@:kernel/sched_stats.h@188
> -likely | 61| 644 ifind()@:fs/inode.c@798
> +unlikely | 258562| 61703 scheduler_tick()@:kernel/sched.c@3756
> -likely | 61220| 241529 acct_update_integrals()@:kernel/tsacct.c@120
> +unlikely | 1189922| 902477 kfree()@:mm/slab.c@3785
> +unlikely | 23| 0 __rmqueue_fallback()@:mm/page_alloc.c@812
> +unlikely | 14376| 9655 rt_policy()@:kernel/sched.c@140

These are all the ones which we got wrong on your setup, yes?

I wonder if assuming that current->audit_context is NULL is realistic
nowadays.



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