[Bug 192353] [NEW] 100% CPU usage during disk I/O with SATA

TheFluffyOne gr_launchpad at thefluffyone.net
Sat Feb 16 11:11:20 UTC 2008


Public bug reported:

I'm seeing 100% CPU usage during SATA disk I/O in a new PC I've put
together. The machine consists of:

MSI K9N6GM-V Mainboard (nForce 410, MCP61)
AMD Sempron LE1100 CPU
512MB Generic 667MHz DDR2 Memory (PC2-5400)
Western Digital WD800AAJS 80GB Hard Drive (SATA-II)
Optiarc AD-7200S DVD Writer (SATA)

OS is Kubuntu Gutsy with all updates to 16/02/2008 (Security and
Recommended enabled via Adept). Filesystem is EXT3, and the sata_nv
driver is in use.

When copying files using Dolphin, I noticed CPU usage hit 100% with most
of it consumed by non-user processes. I ran a few simple tests along
with "vmstat 5" -- a few lines of vmstat output are included for each
test (note: testfile grew to about 1.5GB before I interrupted dd).

$ dd if=/dev/zero of=testfile

procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 2  1  47968   4896    440 244308    0    0    10 16604  236  173  1 63  0 36
 1  1  47968   5060    400 244132    0    0     2 19929  240  169  1 79  0 20
 1  1  47968   4600    476 244724    0    0    26 21610  254  218  2 84  0 14
 0  1  47968   5916    512 243336    0    0     1 22442  252  209  2 91  0  7

$ cp testfile anotherfile

procs -----------memory---------- ---swap-- -----io---- -system-- ----cpu----
 r  b   swpd   free   buff  cache   si   so    bi    bo   in   cs us sy id wa
 0  1  47968   5744   1136 241456    0    0 27061 27391  525  524  3 48  0 50
 1  0  47968   5320    732 242356    0    0 25549 25754  522  507  1 46  0 53
 1  0  47968   5472    836 242096    0    0 26468 25763  521  570  1 48  0 51
 1  1  47968   5204    768 242352    0    0 25908 26580  523  502  1 46  0 53

SATA controller as listed by lspci:

00:08.0 IDE interface: nVidia Corporation MCP61 SATA Controller (rev a2)

References to the hard drive from dmesg:

[   24.183650] ata1.00: ATA-7: WDC WD800AAJS-00PSA0, 05.06H05, max UDMA/133
[   25.008131] scsi 0:0:0:0: Direct-Access     ATA      WDC WD800AAJS-00 05.0 PQ: 0 ANSI: 5

DMA-related information for the hard drive from hdparm:

DMA: mdma0 mdma1 mdma2 udma0 udma1 udma2 udma3 udma4 udma5 *udma6
  Cycle time: min=120ns recommended=120ns

The DVD writer info from dmesg:

[   24.828310] ata2.00: ATAPI: Optiarc DVD RW AD-7200S, 1.01, max UDMA/100
[   25.009770] scsi 1:0:0:0: CD-ROM            Optiarc  DVD RW AD-7200S  1.01 PQ: 0 ANSI: 5

And finally a few lines from top whilst copying 2GB of files using
Dolphin:

Tasks: 108 total,   3 running, 104 sleeping,   0 stopped,   1 zombie
Cpu(s):  5.3%us, 26.2%sy,  0.0%ni,  0.0%id, 67.4%wa,  0.3%hi,  0.7%si,  0.0%st
Mem:    450688k total,   444776k used,     5912k free,      700k buffers
Swap:  1020116k total,    35772k used,   984344k free,   243576k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
14408 bob       18   0 26408 5484 3884 R 17.3  1.2   0:14.64 kio_file
 5781 bob       15   0 47312 8800 5340 S  5.6  2.0   0:08.94 artsd
14021 root      15   0     0    0    0 D  4.0  0.0   0:07.14 pdflush
  169 root      10  -5     0    0    0 S  1.7  0.0   0:09.56 kswapd0
 4022 root      10  -5     0    0    0 S  1.7  0.0   0:06.84 kjournald
 4844 root      15   0 57996  44m 5396 S  0.7 10.1   5:54.90 Xorg
 5716 bob       15   0 25844 3120 1764 S  0.7  0.7   0:02.41 dcopserver
 5739 bob       15   0 32524  12m 9.9m S  0.7  2.9   0:03.44 kio_uiserver
13846 bob       15   0 43272  21m  17m S  0.7  4.9   0:15.28 d3lphin
    1 root      15   0  2952 1856  532 S  0.0  0.4   0:01.16 init

** Affects: linux-meta (Ubuntu)
     Importance: Undecided
         Status: New

-- 
100% CPU usage during disk I/O with SATA
https://bugs.launchpad.net/bugs/192353
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