X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=doc%2Fman%2Flttng-ust.3;h=2c58fba19197cbfe1fc89d86f3f328b1c6cf3f69;hb=b11abb674e50c67e3410ab2bd5d0a263e88b73ba;hp=55de9fd2d88cea5de0cd1fa04f6eba46c4371efd;hpb=f6df8626c40e58c39e83215a5bdbdf7a29038c35;p=lttng-ust.git diff --git a/doc/man/lttng-ust.3 b/doc/man/lttng-ust.3 index 55de9fd2..2c58fba1 100644 --- a/doc/man/lttng-ust.3 +++ b/doc/man/lttng-ust.3 @@ -366,9 +366,13 @@ Pthread identifier. Can be used on architectures where pthread_t maps nicely to an unsigned long type. .PP -.SH "BASE ADDRESS STATEDUMP" +.SH "BASE ADDRESS STATEDUMP (Experimental feature)" .PP +Warning: This is an experimental feature known to cause deadlocks when the +traced application uses fork, clone or daemon. Only use it for debugging and +testing. Do NOT use it in production. + If an application that uses liblttng-ust.so becomes part of a session, information about its currently loaded shared objects will be traced to the session at session-enable time. To record this information, the following event @@ -377,16 +381,17 @@ needs to be enabled: .IP "ust_baddr_statedump:soinfo" This event is used to trace a currently loaded shared object. The base address (where the dynamic linker has placed the shared object) is recorded in the -baddr-field. The path to the shared object gets recorded in the sopath-field -(as string). The file size of the loaded object (in bytes) is recorded to the -size-field and its time of last modification (in seconds since Epoch) is -recorded in the mtime-field. -.PP -If the event above is enabled, a series of ust_baddr_statedump:soinfo events is -recorded at session-enable time, that represents the state of currently loaded -shared objects (of the traced application). If this information gets combined -with the lttng-ust-dl(3) instrumentation, all aspects of dynamic loading that -are relevant for symbol and linenumber-lookup are traced by LTTng. +"baddr" field. The path to the shared object gets recorded in the +"sopath" field (as string). The file size of the loaded object (in +bytes) is recorded to the "size" field and its time of last modification +(in seconds since Epoch) is recorded in the "mtime" field. +.PP +If the event above is enabled, a series of "ust_baddr_statedump:soinfo" +events is recorded at session-enable time. It represents the state of +currently loaded shared objects for the traced process. If this +information gets combined with the lttng-ust-dl(3) instrumentation, all +aspects of dynamic loading that are relevant for symbol and +line number lookup are traced by LTTng. .PP .SH "ENVIRONMENT VARIABLES" @@ -404,8 +409,8 @@ specified in milliseconds. The value 0 means "don't wait". The value recommended for applications with time constraints on the process startup time. .PP -.IP "LTTNG_UST_WITHOUT_BADDR_STATEDUMP" -Prevent liblttng-ust to perform a base-address statedump on session-enable. +.IP "LTTNG_UST_WITH_EXPERIMENTAL_BADDR_STATEDUMP" +Experimentally allow liblttng-ust to perform a base-address statedump on session-enable. .PP .SH "SEE ALSO"