X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=doc%2Fman%2Flttng-ust.3.txt;h=5c9c9f5de2167addcb4427aaedf5a581c456b754;hb=ca08b2bf6b42da4c1ec65e60ffc26384d317a15c;hp=28d66f2565b3af2b9e54f01cbb660220c6002d3e;hpb=b2c5f61a9cb94a79c35167450666e540b3e0fffe;p=lttng-ust.git diff --git a/doc/man/lttng-ust.3.txt b/doc/man/lttng-ust.3.txt index 28d66f25..5c9c9f5d 100644 --- a/doc/man/lttng-ust.3.txt +++ b/doc/man/lttng-ust.3.txt @@ -1293,11 +1293,15 @@ are located in a specific directory under `$LTTNG_HOME` (or `$HOME` if `$LTTNG_HOME` is not set). `LTTNG_UST_ALLOW_BLOCKING`:: - If set, allow application to retry event tracing when there's + If set, allow the application to retry event tracing when there's no space left for the event record in the sub-buffer, therefore effectively blocking the application until space is made available - or timeout is reached. This only has effect on channels with - `blocking-timeout` set. + or the configured timeout is reached. ++ +To allow an application to block during tracing, you also need to +specify a blocking timeout when you create a channel with the +nloption:--blocking-timeout option of the man:lttng-enable-channel(1) +command. + This option can be useful in workloads generating very large trace data throughput, where blocking the application is an acceptable trade-off to @@ -1313,7 +1317,7 @@ affect application timings. https://github.com/lttng/lttng-ust/tree/master/doc/examples/clock-override[`examples/clock-override`]. `LTTNG_UST_DEBUG`:: - Activates `liblttng-ust`'s debug and error output if set to `1`. + If set, enable `liblttng-ust`'s debug and error output. `LTTNG_UST_GETCPU_PLUGIN`:: Path to the shared object which acts as the `getcpu()` override @@ -1332,9 +1336,8 @@ with time constraints on the process startup time. Default: {lttng_ust_register_timeout}. `LTTNG_UST_WITHOUT_BADDR_STATEDUMP`:: - Prevents `liblttng-ust` from performing a base address state dump - (see the <> section above) if - set to `1`. + If set, prevents `liblttng-ust` from performing a base address state + dump (see the <> section above). include::common-footer.txt[]