Date: Wed, 7 May 2003 18:34:27 -0400 (EDT) From: Andre Guibert de Bruet <andy@siliconlandmark.com> To: current@freebsd.org Subject: High CPU utilization even with DMA enabled? Message-ID: <20030507181628.J30571@alpha.siliconlandmark.com>
next in thread | raw e-mail | index | archive | help
Hi,
Here's the output of top while moving a large file from one disk to
another on my otherwise idle desktop machine:
PID USERNAME PRI NICE SIZE RES STATE C TIME WCPU CPU COMMAND
26 root -68 -187 0K 12K WAIT 0 141:36 79.98% 79.98% irq7: dc0 ohci0
11 root -16 20 0K 12K RUN 1 13:45 34.86% 34.86% idle: cpu1
12 root -16 20 0K 12K CPU0 0 13:46 30.32% 30.32% idle: cpu0
21069 root 116 0 608K 136K RUN 1 0:58 16.41% 16.41% mv
647 dnetc 128 20 1032K 656K RUN 0 826:51 9.28% 9.28% dnetc
656 dnetc 128 20 1016K 556K RUN 0 829:36 8.15% 8.15% dnetc
14 root -48 -167 0K 12K WAIT 0 9:27 4.88% 4.88% swi7: tty:sio clock
3 root -8 0 0K 12K g_up 0 4:06 2.88% 2.88% g_up
24 root -64 -183 0K 12K WAIT 0 0:27 1.22% 1.22% irq15: ata1
This system has the following IDE configuration:
ATA channel 0:
Master: no device present
Slave: acd0 <DVD-ROM BDV316C/VER .20H> ATA/ATAPI rev 0
ATA channel 1:
Master: ad2 <WDC WD2500JB-34EVA0/15.05R15> ATA/ATAPI rev 6
Slave: no device present
ATA channel 2:
Master: ad4 <Maxtor 6Y200P0/YAR41VW0> ATA/ATAPI rev 7
Slave: no device present
ATA channel 3:
Master: ad6 <Maxtor 6Y200P0/YAR41VW0> ATA/ATAPI rev 7
Slave: no device present
The files I'm moving are several gigabytes large and they're going from
ad6 to ad2. The motherboard is an Asus A7M266D, with onboard ATA100
channels (0,1) and a Promise Tech ATA133 card installed (channels 2,3).
Now, I realize that copying a file from one disk to another requires cpu
cycles even with DMA enabled, but is 80% of cpu usage to be expected?
Also, wouldn't one expect process id 24 (irq15: ata1) to be using CPU
during such transfers?
Regards,
PS: dmesg, pciconf -vl and other information is available, if needed.
> Andre Guibert de Bruet | Enterprise Software Consultant >
> Silicon Landmark, LLC. | http://siliconlandmark.com/ >
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20030507181628.J30571>