System Calls OptimizationΒΆ
The use of the TZ environment variable can dramatically reduce the number of system calls and kernel context switches performed by the application.
The localtime() function in glibc checks whether the TZ environment
variable is set. If it is not set, then glibc will use the stat() system
call every time localtime() is called, even with vDSO in place.
Setting the TZ environment variable to :/etc/localtime (or some other
timezone file of your choice) for a process will save glibc from making those
extra unnecessary system calls (Notice the column : prefix before the file
path).
The variable can be set either from the shell, i.e.
export TZ=:/etc/localtime
or directly from inside the dovecot configuration file
import_environment = $import_environment TZ=:/etc/localtime
Note that a simple reload is not sufficient for the change to take effect. A restart is required.
See also:
