Archive for the tag 'I/O'

SBDavid
Oct 20th, 2012

/proc/[pid]/io - Display the IO accounting fields

/proc/[pid]/io - Display the IO accounting fields

This file contains IO statistics for each running process.

# dd if=/dev/zero of=/tmp/test.dat &
[1] 3828
–
# cat /proc/3828/io
rchar: 323934931
wchar: 323929600
syscr: 632687
syscw: 632675
read_bytes: 0
write_bytes: 323932160
cancelled_write_bytes: 0

Field Descriptions:
rchar - bytes read
wchar - byres written
syscr - number of read syscalls
syscw - number of write syscalls
read_bytes - number of bytes caused by this process to read from underlying storage
write_bytes - number of bytes caused by this process to written from underlying storage

SBDavid
Jan 13th, 2010

Query/enable (E)IDE 32-bit I/O support using hdparm

Query/enable (E)IDE 32-bit I/O support using hdparm

Check your current disk status.

hdparm -tT /dev/hda

-c Query/enable (E)IDE 32-bit I/O support. A numeric parameter can be used to enable/disable 32-bit I/O support: Currently sup-ported values include 0 to disable 32-bit I/O support, 1 to enable 32-bit data transfers, and 3 to enable 32-bit data trans-fers with a special sync sequence required by many chipsets.

The value 3 works with nearly all 32-bit IDE chipsets, but incurs slightly more overhead. Note that “32-bit” refers to data transfers across a PCI or VLB bus to