5.4 Buffer Sizes

The size of each buffer can be tuned on a per-consumer basis. Separate options are provided to tune each buffer size, as shown in the following table.

Buffer

Size Option

Aggregation

aggsize

Principal

bufsize

Speculative

specsize

Each of these options is set with a value that denotes the size. As with any size option, the value might have an optional size suffix. See Chapter 10, Options and Tunables for more details.

For example, you would set the buffer size to 10 megabytes on the dtrace command line as follows:

# dtrace -P syscall -x bufsize=10m

Alternatively, you can use the -b option with the dtrace command:

# dtrace -P syscall -b 10m

Finally, you can set bufsize by using a pragma, for example:

#pragma D option bufsize=10m

The buffer size that you select denotes the size of the buffer on each CPU. Moreover, for the switch buffer policy, bufsize denotes the size of each buffer on each CPU. The default buffer size is four megabytes.