From: Andrew Morton <akpm@digeo.com>
To: Paolo Ciarrocchi <ciarrocchi@linuxmail.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: LMbench2.0 results
Date: Sun, 08 Sep 2002 00:51:21 -0700 [thread overview]
Message-ID: <3D7B0179.2F9ED774@digeo.com> (raw)
In-Reply-To: 20020907180937.16081.qmail@linuxmail.org
Paolo Ciarrocchi wrote:
>
> ...
> File & VM system latencies in microseconds - smaller is better
> --------------------------------------------------------------
> Host OS 0K File 10K File Mmap Prot Page
> Create Delete Create Delete Latency Fault Fault
> --------- ------------- ------ ------ ------ ------ ------- ----- -----
> frodo Linux 2.4.18 68.9 16.0 185.8 31.6 425.0 0.789 2.00000
> frodo Linux 2.4.19 68.9 14.9 186.5 29.8 416.0 0.798 2.00000
> frodo Linux 2.5.33 77.8 19.1 211.6 38.3 774.0 0.832 3.00000
> frodo Linux 2.5.33x 77.2 18.8 206.7 37.0 769.0 0.823 3.00000
>
The create/delete performance is filesystem-specific.
profiling lat_fs on ext3:
c0170b70 236 0.372293 ext3_get_inode_loc
c014354c 278 0.438548 __find_get_block
c017cbf0 284 0.448013 journal_cancel_revoke
c017ee24 291 0.459056 journal_add_journal_head
c0171030 307 0.484296 ext3_do_update_inode
c017856c 353 0.556861 journal_get_write_access
c0178088 487 0.768248 do_get_write_access
c0114744 530 0.836081 smp_apic_timer_interrupt
c0178a84 559 0.881829 journal_dirty_metadata
c0130644 832 1.31249 generic_file_write_nolock
c0172654 2903 4.57951 ext3_add_entry
c016ca10 3636 5.73583 ext3_check_dir_entry
c0107048 47078 74.2661 poll_idle
ext3_check_dir_entry is just sanity checking. hmm.
on ext2:
c017f3ec 138 0.239971 ext2_free_blocks
c012f560 147 0.255621 unlock_page
c017f954 148 0.25736 ext2_new_block
c017f2f0 154 0.267793 ext2_get_group_desc
c0181958 162 0.281705 ext2_new_inode
c014354c 182 0.316483 __find_get_block
c0154f64 184 0.319961 __d_lookup
c0109bc0 232 0.403429 apic_timer_interrupt
c0143cc4 455 0.791208 __block_prepare_write
c0114744 459 0.798164 smp_apic_timer_interrupt
c0130644 1634 2.84139 generic_file_write_nolock
c0180c64 6084 10.5796 ext2_add_link
c0107048 42472 73.8554 poll_idle
This is mostly in ext2_match() - comparing strings while
searching the directory. memcmp().
ext3 with hashed index directories:
c01803dc 292 0.495251 journal_unlock_journal_head
c0170b70 313 0.530868 ext3_get_inode_loc
c01801a4 412 0.698779 journal_add_journal_head
c014354c 455 0.77171 __find_get_block
c0171030 489 0.829376 ext3_do_update_inode
c017df70 515 0.873474 journal_cancel_revoke
c01798ec 555 0.941316 journal_get_write_access
c0173208 568 0.963365 ext3_add_entry
c0179408 804 1.36364 do_get_write_access
c0179e04 838 1.4213 journal_dirty_metadata
c0130644 1127 1.91147 generic_file_write_nolock
c0107048 44117 74.8253 poll_idle
And yet the test (which tries to run for a fixed walltime)
seems to do the same amount of work. No idea what's up
with that.
Lessons: use an indexed-directory filesystem, and consistency
checking costs.
next prev parent reply other threads:[~2002-09-08 7:32 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2002-09-07 18:09 LMbench2.0 results Paolo Ciarrocchi
2002-09-08 7:51 ` Andrew Morton [this message]
-- strict thread matches above, loose matches on Subject: below --
2002-09-22 12:42 Paolo Ciarrocchi
2002-09-14 18:26 Paolo Ciarrocchi
2002-09-15 18:08 ` Pavel Machek
2002-09-07 18:04 Paolo Ciarrocchi
2002-09-13 22:49 ` Pavel Machek
2002-09-07 14:09 Shane Shrybman
2002-09-07 12:40 Paolo Ciarrocchi
2002-09-07 12:18 Paolo Ciarrocchi
2002-09-07 12:27 ` Jeff Garzik
2002-09-07 18:53 ` Rik van Riel
2002-09-07 21:44 ` Alan Cox
2002-09-13 22:46 ` Pavel Machek
2002-09-07 14:33 ` James Morris
2002-09-09 22:22 ` Cliff White
2002-09-07 16:20 ` Andrew Morton
2002-09-07 20:03 ` William Lee Irwin III
2002-09-07 23:12 ` Andrew Morton
2002-09-07 23:01 ` William Lee Irwin III
2002-09-07 23:44 ` Martin J. Bligh
2002-09-08 17:07 ` Alan Cox
2002-09-08 18:11 ` Martin J. Bligh
2002-09-08 18:40 ` Andrew Morton
2002-09-08 20:48 ` Hugh Dickins
2002-09-08 21:51 ` Andrew Morton
2002-09-09 21:13 ` Alan Cox
2002-09-09 21:44 ` Andrew Morton
2002-09-09 22:09 ` Alan Cox
2002-09-08 7:51 ` Andrew Morton
2002-09-08 7:37 ` David S. Miller
2002-09-08 8:28 ` William Lee Irwin III
2002-09-08 8:25 ` David S. Miller
2002-09-08 9:12 ` William Lee Irwin III
2002-09-08 20:02 ` Daniel Phillips
2002-09-09 13:37 ` Rik van Riel
2002-09-09 16:16 ` Daniel Phillips
2002-09-09 16:26 ` Martin J. Bligh
2002-09-09 16:55 ` Daniel Phillips
2002-09-09 17:24 ` Martin J. Bligh
2002-09-09 21:11 ` Alan Cox
2002-09-09 16:52 ` Andrew Morton
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