2.6.7-mm1 I/O regression ?

From: FabF
Date: Mon Jun 21 2004 - 15:49:55 EST


Hi,

I've got strange I/O regression from 2.6.7-mm1.Here's a small fgrep
report :

2.6.7-mm1 (worst results ever seen)
-----------------------------------
Grepping /usr/bin :
23% cpu - 86.16 RT Sec - 1.77 Sec in KM
Entries scanned :
1569
90192 Kb analyzed this time

2.6.7-mm1 vm profile snippet
----------------------------

61.9360 vmlinux poll_idle
0.8899 vmlinux mark_offset_tsc
0.8857 vmlinux __copy_to_user_ll
0.6136 vmlinux mask_and_ack_8259A
0.5605 vmlinux do_anonymous_page
0.3445 vmlinux unix_poll
0.3240 vmlinux __switch_to
0.2016 vmlinux enable_8259A_irq
0.1448 vmlinux do_select
0.1336 vmlinux get_exec_dcookie
0.1128 vmlinux fget
0.0959 vmlinux schedule

2.6.7 (best results ever seen)
------------------------------
Grepping /usr/bin :
48% cpu - 37.61 RT Sec - 1.46 Sec in KM
Entries scanned :
1569
90184 Kb analyzed this time

2.6.7 vm Profile snippet
------------------------
80.4850 vmlinux poll_idle
0.9149 vmlinux mark_offset_tsc
0.7879 vmlinux mask_and_ack_8259A
0.4552 vmlinux do_wp_page
0.3943 vmlinux do_anonymous_page
0.2559 vmlinux enable_8259A_irq
0.2464 vmlinux __copy_to_user_ll
0.1721 vmlinux unix_poll
0.1302 vmlinux irq_entries_start

Well, profiles don't give a clue but fgrep RT delta is impressive.Did I missed something ?

PS : Those tests were made on ext3 partition.

Regards,
FabF

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