diff options
Diffstat (limited to 'man/systemd-analyze.xml')
-rw-r--r-- | man/systemd-analyze.xml | 15 |
1 files changed, 13 insertions, 2 deletions
diff --git a/man/systemd-analyze.xml b/man/systemd-analyze.xml index 5dce2ae8fb..7112362ac5 100644 --- a/man/systemd-analyze.xml +++ b/man/systemd-analyze.xml @@ -178,7 +178,13 @@ multi-user.target reached after 47.820s in userspace initialization of one service might be slow simply because it waits for the initialization of another service to complete. Also note: <command>systemd-analyze blame</command> doesn't display results for services with <varname>Type=simple</varname>, because systemd considers such services to be started - immediately, hence no measurement of the initialization delays can be done.</para> + immediately, hence no measurement of the initialization delays can be done. Also note that this command + only shows the time units took for starting up, it does not show how long unit jobs spent in the + execution queue. In particular it shows the time units spent in <literal>activating</literal> state, + which is not defined for units such as device units that transition directly from + <literal>inactive</literal> to <literal>active</literal>. This command hence gives an impression of the + performance of program code, but cannot accurately reflect latency introduced by waiting for + hardware and similar events.</para> <example> <title><command>Show which units took the most time during boot</command></title> @@ -202,7 +208,12 @@ multi-user.target reached after 47.820s in userspace <replaceable>UNIT</replaceable>s or for the default target otherwise). The time after the unit is active or started is printed after the "@" character. The time the unit takes to start is printed after the "+" character. Note that the output might be misleading as the initialization of services might - depend on socket activation and because of the parallel execution of units.</para> + depend on socket activation and because of the parallel execution of units. Also, similar to the + <command>blame</command> command, this only takes into account the time units spent in + <literal>activating</literal> state, and hence does not cover units that never went through an + <literal>activating</literal> state (such as device units that transition directly from + <literal>inactive</literal> to <literal>active</literal>). Moreover it does not show information on + jobs (and in particular not jobs that timed out).</para> <example> <title><command>systemd-analyze time</command></title> |