mirror of
https://github.com/Stichting-MINIX-Research-Foundation/netbsd.git
synced 2025-09-11 16:15:07 -04:00
83 lines
2.7 KiB
Plaintext
83 lines
2.7 KiB
Plaintext
The following are demonstrations of the rfsio.d script.
|
|
|
|
|
|
|
|
Here we trace file read() activity that has fully missed the cache and
|
|
must be read from disk,
|
|
|
|
# ./rfsio.d
|
|
|
|
Read IOPS (count)
|
|
/ logical 7
|
|
/extra1 physical 162
|
|
/boot logical 235
|
|
/boot physical 410
|
|
/extra1 logical 9514
|
|
|
|
Read Bandwidth (bytes)
|
|
/ logical 533
|
|
/boot logical 1502386
|
|
/boot physical 1512960
|
|
/extra1 physical 97153024
|
|
/extra1 logical 97228668
|
|
|
|
Total File System miss-rate: 100%
|
|
^C
|
|
|
|
The miss rate of 100% means that all of the file system activity missed
|
|
the cache, and had to read from disk.
|
|
|
|
|
|
|
|
The following demonstrates file read() activity to the root filesystem
|
|
that mostly returned from the file system cache.
|
|
|
|
# ./rfsio.d
|
|
|
|
Read IOPS (count)
|
|
/ physical 1
|
|
/extra1 physical 9
|
|
/devices logical 9
|
|
/ logical 15
|
|
/extra1 logical 4096
|
|
|
|
Read Bandwidth (bytes)
|
|
/devices logical 9
|
|
/ logical 949
|
|
/ physical 8192
|
|
/extra1 physical 917504
|
|
/extra1 logical 4194304
|
|
|
|
Total File System miss-rate: 22%
|
|
^C
|
|
|
|
The total miss-rate was 22%, which is based on the bytes transferred that
|
|
missed the cache.
|
|
|
|
|
|
|
|
|
|
Now for an unusual demonstration,
|
|
|
|
# ./rfsio.d
|
|
|
|
Read IOPS (count)
|
|
/devices logical 1
|
|
/ logical 10
|
|
/extra1 physical 106
|
|
/extra1 logical 6337
|
|
|
|
Read Bandwidth (bytes)
|
|
/devices logical 2
|
|
/ logical 961
|
|
/extra1 logical 64846450
|
|
/extra1 physical 66151424
|
|
|
|
Total File System miss-rate: 102%
|
|
^C
|
|
|
|
Here the miss-rate is 102%, which indicates that more data was read from
|
|
disk than was requested; this can occur due to UFS read-ahead, which
|
|
assists the performance of sequential disk activity at the small risk of
|
|
reading too much data.
|