How to Check System Call Statistics (sar -c)
Display system call statistics by using the sar -c command.
$ sar -c 00:00:00 scall/s sread/s swrit/s fork/s exec/s rchar/s wchar/s 01:00:00 38 2 2 0.00 0.00 149 120 |
The following table describes the system call categories that are reported by the -c option. Typically, reads and writes account for about half of the total system calls, although the percentage varies greatly with the activities that are being performed by the system.
Table 24–9 Output From the sar -c Command|
Field Name |
Description |
|---|---|
|
scall/s |
All types of system calls per second (generally about 30 per second on a system with 4 to 6 users). |
|
sread/s |
read system calls per second. |
|
swrit/s |
write system calls per second. |
|
fork/s |
fork system calls per second (about 0.5 per second on a system with 4 to 6 users). This number will increase if shell scripts are running. |
|
exec/s |
exec system calls per second. If exec/s divided by fork/s is greater than three, look for inefficient PATH variables. |
|
rchar/s |
Characters (bytes) transferred by read system calls per second. |
|
wchar/s |
Characters (bytes) transferred by write system calls per second. |
Example—Checking System Call Statistics
The following abbreviated example shows output from the sar -c command.
$ sar -c SunOS venus 5.9 Generic sun4u 06/24/2001 00:00:00 scall/s sread/s swrit/s fork/s exec/s rchar/s wchar/s 01:00:00 38 2 2 0.00 0.00 149 120 02:00:02 38 2 2 0.00 0.00 149 120 03:00:00 42 2 2 0.05 0.05 218 147 04:00:00 39 2 2 0.01 0.00 155 123 05:00:01 38 2 2 0.00 0.00 150 120 06:00:00 38 2 2 0.01 0.00 149 120 Average 50 4 3 0.02 0.02 532 238 |
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