RE: Discrepancies between Oprofile and vmstat II

From: Styner, Douglas W
Date: Mon Apr 27 2009 - 18:16:06 EST



> I believe so, but will confirm.
>
> > opcontrol -e=CPU_CLK_UNHALTED:80000 -e=LLC_MISSES:6000
> >
> > Using another profiling tool to confirm, we see 74.784% user, 25.174% > > kernel.
>
> Just verifying -- you also see it when you use a shorter period than 80000 > right?

Confirmed. Changes in profile appear to be due to increased sampling by oprofile with lower value.

Linux OLTP Performance summary
Kernel# Speedup(x) Intr/s CtxSw/s us% sys% idle% iowait%
2.6.30-rc3 1.000 30593 43976 74 25 0 1
2.6.30-rc3 1.001 30534 43210 75 25 0 0

Server configurations:
Intel Xeon Quad-core 2.0GHz 2 cpus/8 cores/8 threads
64GB memory, 3 qle2462 FC HBA, 450 spindles (30 logical units)

======oprofile CPU_CLK_UNHALTED for top 30 functions
-e=CPU_CLK_UNHALTED:80000 -e=CPU_CLK_UNHALTED:20000
Cycles% 2.6.30-rc3 Cycles% 2.6.30-rc3
68.5544 <database> 65.6876 <database>
1.1859 qla24xx_start_scsi 1.1033 kstat_irqs_cpu
0.9436 qla24xx_intr_handler 1.0575 rb_get_reader_page
0.8307 __schedule 1.0034 qla24xx_start_scsi
0.7194 kmem_cache_alloc 0.9305 qla24xx_intr_handler
0.5026 __blockdev_direct_IO 0.8410 ring_buffer_consume
0.4319 __sigsetjmp 0.8160 __schedule
0.4244 scsi_request_fn 0.5683 kmem_cache_alloc
0.3853 rb_get_reader_page 0.4517 __sigsetjmp
0.3777 __switch_to 0.4413 unmap_vmas
0.3552 __list_add 0.3809 __blockdev_direct_IO
0.3552 task_rq_lock 0.3726 __switch_to
0.3371 try_to_wake_up 0.3310 __list_add
0.3221 ring_buffer_consume 0.3206 task_rq_lock
0.2844 aio_complete 0.3123 scsi_request_fn
0.2588 memmove 0.2977 aio_complete
0.2588 mod_timer 0.2914 try_to_wake_up
0.2558 generic_make_request 0.2644 page_fault
0.2543 tcp_sendmsg 0.2436 kmem_cache_free
0.2528 copy_user_generic_string 0.2415 scsi_device_unbusy
0.2468 lock_timer_base 0.2352 copy_user_generic_string
0.2468 memset_c 0.2311 memmove
0.2288 blk_queue_end_tag 0.2227 lock_timer_base
0.2257 qla2x00_process_completed_re0.2123 generic_make_request
0.2212 kref_get 0.2103 kfree
0.2182 mempool_free 0.2040 find_vma
0.2137 sd_prep_fn 0.2019 sd_prep_fn
0.2122 e1000_xmit_frame 0.2019 blk_queue_end_tag
0.2062 dequeue_rt_stack 0.2019 tcp_sendmsg
0.2047 scsi_device_unbusy 0.1998 qla2x00_process_completed_re
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