Messages in this thread | | | Date | Tue, 28 Aug 2007 17:09:50 +0200 | From | John Sigler <> | Subject | Re: pdflush preemption |
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Daniel Walker wrote:
> John Sigler wrote: > >> Why does pdflush kick in to ruin my party? :-) >> The expected latency is ~600 µs. >> http://linux.kernel.free.fr/latency/pdflush.trace >> Does ide_inb mean I'm reading from the disk? > > Does your real time application lock its memory, or allow itself to be > swapped?
Now that you mention it, I do remember reading this page: http://rt.wiki.kernel.org/index.php/HOWTO:_Build_an_RT-application
There is no swap configured on the system, and 90% of the 256 MB of RAM are free, according to /proc/meminfo, and the system is otherwise idle.
I don't think this is a major page fault. Am I wrong?
# /bin/time ./check_dektec_output2 4140063957 38000000 2632 30 0.02user 0.31system 0:20.02elapsed 1%CPU (0avgtext+0avgdata 0maxresident)k 0inputs+0outputs (0major+270minor)pagefaults 0swaps ^^^^^^
# cat /proc/vmstat nr_free_pages 59351 nr_inactive 1465 nr_active 1830 nr_anon_pages 486 nr_mapped 569 nr_file_pages 2813 nr_dirty 0 nr_writeback 0 nr_slab_reclaimable 449 nr_slab_unreclaimable 663 nr_page_table_pages 41 nr_unstable 0 nr_bounce 0 nr_vmscan_write 0 pgpgin 8197 pgpgout 113 pswpin 0 pswpout 0 pgalloc_dma 0 pgalloc_normal 27260 pgfree 86682 pgactivate 1372 pgdeactivate 0 pgfault 77490 pgmajfault 121 pgrefill_dma 0 pgrefill_normal 0 pgsteal_dma 0 pgsteal_normal 0 pgscan_kswapd_dma 0 pgscan_kswapd_normal 0 pgscan_direct_dma 0 pgscan_direct_normal 0 pginodesteal 0 slabs_scanned 0 kswapd_steal 0 kswapd_inodesteal 0 pageoutrun 0 allocstall 0 pgrotated 0
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