Re: Help understanding slow down

Martin J. Bligh
2004-05-24T14:14:52Z

I'm curious where all those kmap_atomic's come from. Do you have
CONFIG_HIGHPTE enabled? If so, please repeat with it off, and see
if that helps ... if not, grab the kcg patch out my tree, and see
where they're coming from (or shove a printk in there doing a dump_stack
for every 10,000 interations or so)

M.

--Phy Prabab <phyprabab@yahoo.com> wrote (on Monday, May 24, 2004 00:21:07 -0700):

> For more information, I ran the same test on 2.4.21
> with profiling enabled:
> 22133 total 0.0102
> 18255 default_idle 351.0577
> 634 do_page_fault 0.4412
> 342 do_no_page 0.3654
> 231 d_lookup 0.8134
> 173 do_anonymous_page 0.2790
> 157 system_call 2.8036
> 157 pte_alloc_atomic 0.2973
> 130 do_wp_page 0.1222
> 102 __find_get_page 1.5000
> 99 atomic_dec_and_lock 1.3750
> 90 handle_mm_fault 0.2616
> 89 zap_page_range 0.0792
> 86 link_path_walk 0.0343
> 62 mraccessf 0.6458
> 59 permission 0.4470
> 56 mrunlock 0.5600
> 42 strncpy_from_user 0.5526
> 40 strnlen_user 0.4545
> 40 __do_generic_file_read 0.0316
> 39 __free_pages 1.2188
> 35 filemap_nopage 0.0648
>
> Also refomated the previous report to make it
> readable:
>
>> 317955 total 0.1302
>> 263633 poll_idle 4545.3966
>> 6764 do_page_fault 5.1951
>> 3650 kmap_atomic 28.2946
>> 3288 __d_lookup 12.0000
>> 1856 atomic_dec_and_lock 30.4262
>> 1823 do_no_page 2.4870
>> 1398 do_anonymous_page 3.1991
>> 1168 link_path_walk 0.5266
>> 1138 find_get_page 19.9649
> 1.2450
>> 1075 nfs_lookup_revalidate 0.7739
>> 1039 page_remove_rmap 5.0437
>> 1006 in_group_p 9.4906
>> 987 handle_mm_fault 2.2742
>> 913 do_wp_page 1.1499
>> 816 finish_task_switch 6.6885
>> 772 tg3_poll 2.6621
>> 762 rpcauth_lookup_credcache 1.3275
>> 722 page_add_file_rmap 4.1257
>> 623 system_call 14.1591
>> 607 strncpy_from_user 6.8202
>>
>> Thanks again!
>> Phy
>>
>>
>>
>> --- William Lee Irwin III <wli@holomorphy.com>
>> wrote:
>> > On Sun, May 23, 2004 at 11:23:37PM -0700, Phy
>> Prabab
>> > wrote:
>> > > Sorry for the late reply. No this is a dual
>> Xeon
>> > > 3.06Ghz. All runs are with the same hardware
>> and
>> > same
>> > > make/build system.
>> > > How do I generate a profile of the system. I
>> have
>> > > alrady compiled profiling and have enabled the
>> > kernel.
>> >
>> > readprofile -n -m /boot/System.map-`uname -r` |
>> sort
>> > -rn -k 1,1 | head -22
>> >
>> > No need for compiled-in support, just boot with
>> > profile=1.
>> >
>> >
>> > -- wli
>>
>>
>>
>>
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