diff options
Diffstat (limited to 'script/mwrap-perl')
| -rw-r--r-- | script/mwrap-perl | 64 |
1 files changed, 57 insertions, 7 deletions
diff --git a/script/mwrap-perl b/script/mwrap-perl index 82629b4..48f5471 100644 --- a/script/mwrap-perl +++ b/script/mwrap-perl @@ -28,8 +28,8 @@ mwrap-perl - run any command under mwrap =head1 SYNOPSIS - # to trace a long-running program and access it via $DIRECTORY/$PID.sock: - MWRAP=socket_dir:$DIRECTORY mwrap-perl COMMAND + # to trace a long-running program and access it via $DIR/$PID.sock: + MWRAP=socket_dir:$DIR mwrap-perl COMMAND # to trace a short-lived command and dump its output to a log: MWRAP=dump_path:$FILENAME mwrap-perl COMMAND @@ -46,14 +46,16 @@ of native (C/C++) functions for non-Perl programs. C<MWRAP> is the only environment variable read. It contains multiple options delimited by C<,> with names and values delimited by C<:> -=item socket_dir:$DIRECTORY +=over 4 + +=item socket_dir:$DIR This launches an embedded HTTP server in each process and binds it -to C<$DIRECTORY/$PID.sock>. C<curl --unix-socket $DIRECTORY/$PID.sock> +to C<$DIR/$PID.sock>. C<curl --unix-socket $DIR/$PID.sock http://0/$PID/> or L<mwrap-rproxy(1p)> may be used to access various endpoints in the HTTP server. -=item: bt:$DEPTH +=item bt:$DEPTH The backtrace depth for L<backtrace(3)> in addition to the Perl file and line number where C<$DEPTH> is a non-negative number. @@ -64,15 +66,63 @@ increase the amount of memory mwrap (and liburcu) itself uses. This is only useful in conjunction with C<socket_dir> +This may be changed via POST request (see below). + Default: 0 =item dump_path:$FILENAME -Dumps the output +Dumps the output at exit to a given filename: total_bytes call_count location -In the future, dumping to a self-describing CSV will be supported +In the future, dumping to a self-describing CSV will be supported. + +=item dump_fd:$DESCRIPTOR + +As with dump_path, but dumps the output to a given file descriptor. + +=back + +=head1 HTTP POST API + +In addition to the various GET endpoints linked via C<http://0/$PID/>, +there are some POST endpoints which are typically accessed via +C<curl --unix-socket $DIR/$PID.sock> + +=over 4 + +=item POST http://0/$PID/reset + +C<curl --unix-socket $DIR/$PID.sock -XPOST http://0/$PID/reset> + +Reset all internal counters. This is not done atomically and does +not release any memory. + +=item POST http://0/$PID/trim + +C<curl --unix-socket $DIR/$PID.sock -XPOST http://0/$PID/trim> + +Runs L<malloc_trim(3)> with a 0 pad value to release unused memory +back to the kernel. In our malloc implementation, this is done +lazily to avoid contention and does not happen unless sleeping threads. + +=item POST http://0/$PID/ctl + +Set various internal knobs. Currently, C<X-Mwrap-BT-Depth> is the +only knob supported: + +C<curl --unix-socket $DIR/$PID.sock -XPOST -HX-Mwrap-BT-Depth:1 http://0/$PID/ctl> + +Using the C<X-Mwrap-BT-Depth> header allows changing the aforementioned +C<bt:> value to a specified depth level. As with C<bt:>, only make small +adjustments as the memory cost can increase exponentially with each step. + +It is typically a good idea to reset (C<http://0/$PID/reset>) after changing +the depth on a running process. + +Headers other than C<X-Mwrap-BT-Depth> may be accepted in the future to +tweak other settings. =back |