X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=doc%2Fman%2Flttng-enable-event.1.txt;fp=doc%2Fman%2Flttng-enable-event.1.txt;h=92fd5f51f22d65910f951edbed665cfed84df63d;hp=b6141b25847a873b4c87a6c997161895c23f8688;hb=c52365cca920b6e600f3209e32c815c4ef0ffc53;hpb=e6142f2e647e83238b1e399b1264e8adb05409f9 diff --git a/doc/man/lttng-enable-event.1.txt b/doc/man/lttng-enable-event.1.txt index b6141b258..92fd5f51f 100644 --- a/doc/man/lttng-enable-event.1.txt +++ b/doc/man/lttng-enable-event.1.txt @@ -178,10 +178,10 @@ argument named `*` (wildcard). [[filter-syntax]] Filter expression syntax ~~~~~~~~~~~~~~~~~~~~~~~~ -Filter expressions can be specified with the option:--filter option -when creating a new event rule. If the filter expression evaluates -to true when executed against the dynamic values of an event's fields -when tracing, the filtering condition passes. +A filter expression can be specified with the option:--filter option +when creating a new event rule. If the filter expression evaluates to +true when executed against the dynamic values of an event's fields when +tracing, the filtering condition passes. NOTE: Make sure to **single-quote** the filter expression when running the command from a shell, as filter expressions typically include @@ -218,13 +218,14 @@ The arithmetic and bitwise operators are :not: supported. The precedence table of the operators above is the same as the one of the C language. Parentheses are supported to bypass this. -The dynamic value of an event field is read by using its name as -a C identifier. +The dynamic value of an event field is read by using its name as a C +identifier. The dynamic value of a statically-known context field is read by prefixing its name with `$ctx.`. Statically-known context fields are context fields added to channels without the `$app.` prefix using the -man:lttng-add-context(1) command. +man:lttng-add-context(1) command. `$ctx.cpu_id` is also available as the +ID of the CPU which emits the event. The dynamic value of an application-specific context field is read by prefixing its name with `$app.` (follows the format used to add such a @@ -260,9 +261,9 @@ $ctx.procname == "lttng*" && (!flag || poel < 34) $app.my_provider:my_context == 17.34e9 || some_enum >= 14 --------------------------------------------------------- -------------------- -filename != "*.log" -------------------- +--------------------------------------- +$ctx.cpu_id == 2 && filename != "*.log" +--------------------------------------- [[log-levels]]