Re: 2.6.7rc1 vs 2.6.0

From: FabF
Date: Sat May 29 2004 - 08:33:28 EST


Martin,

When profiling latest mm against some fgrep I've got the following:

Extracting ext3 relevant fx:

Occ / Function
71 ext3_get_block_handle
68 ext3_dx_find_entry
57 ext3_get_branch
48 ext3_getblk
40 ext3_do_update_inode
35 ext3_find_entry
35 ext3_read_inode
31 ext3_block_to_path
30 ext3_get_inode_block
20 ext3_get_block
19 ext3_htree_store_dirent
15 ext3_lookup
12 ext3_release_file
12 ext3fs_dirhash
11 ext3_get_inode_loc
10 ext3_check_dir_entry

All those ext3_fxs consume almost 0.1% CPU and are not called as much as I thought

(e.g.
9573 3.2735 vmlinux __copy_to_user_ll
6914 2.3642 vmlinux mark_offset_tsc
4399 1.5042 vmlinux mask_and_ack_8259A
2703 0.9243 vmlinux fast_clear_page
1750 0.5984 vmlinux enable_8259A_irq
933 0.3190 vmlinux default_idle
826 0.2824 vmlinux irq_entries_start
822 0.2811 vmlinux ide_outb
614 0.2100 vmlinux apic_timer_interrupt
513 0.1754 vmlinux ide_inb
355 0.1214 vmlinux page_fault
331 0.1132 vmlinux find_vma
243 0.0831 vmlinux get_exec_dcookie
189 0.0646 vmlinux __d_lookup
170 0.0581 vmlinux unix_poll
160 0.0547 vmlinux do_generic_mapping_read
159 0.0544 vmlinux radix_tree_delete
155 0.0530 vmlinux __rmqueue
155 0.0530 vmlinux schedule
153 0.0523 vmlinux buffered_rmqueue
143 0.0489 vmlinux handle_mm_fault
133 0.0455 vmlinux disable_8259A_irq
130 0.0445 vmlinux delay_tsc
127 0.0434 vmlinux __page_cache_release
125 0.0427 vmlinux __find_get_block
124 0.0424 vmlinux __alloc_pages
124 0.0424 vmlinux kmem_cache_alloc
112 0.0383 vmlinux page_add_anon_rmap
102 0.0349 vmlinux link_path_walk
...)

So I guess we can consider the 2.6 / 2.6.7 I/O regression not fs relevant (ie ext3) in this case ....

PS: I'll try to bring same profile for 2.6.0.

Regards,
FabF

On Tue, 2004-05-25 at 16:27, Martin J. Bligh wrote:
> > Here's trivial fgrep vs report (using ffb1) :
> >
> > 2.6.7rc1 :
> > Grepping /usr/bin :
> > 45% cpu - 38.06 RT Sec - 1.10 Sec in KM
> > Entries scanned : 1527
> > 85112 Kb analyzed this time
> >
> > 2.6.0 :
> > Grepping /usr/bin :
> > 51% cpu - 33.12 RT Sec - 1.10 Sec in KM
> > Entries scanned :1527
> > 85112 Kb analyzed this time
> >
> > This is done against ext3 fs. Same .config, same box, same box state.
> > What relevance could explain this 5s delta ? IOW, what big ext3, mm new functionnalities have been plugged in-between ?
>
> Take kernel profiles of both (see Documentation/basic_profiling.txt)
>
> M.
>
>

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