Where more is:
* Changed the default format to xml, so that all traces don't suddenly
change as of this commit. Someone is going to need to start passing a
flag to all their servers, but let's worry about that later.
* Changed the copyright headers to be the correct filename.
* Include paths should be specified from the root.
backtrace() gives a list of return addresses, which means that addr2line will
print out the line after the caller. GetStackTrace returns the list of caller
addresses, so the addr2line results should be accurate. The flow profiler was
also changed to use the new backtracing code, so flow profiles will now be
accurate as well. Unfortunately, the abseil code doesn't work on MacOS, so we
still fall back to backtrace() in this case.
For the stack unwinder to work, we must disable -fomit-frame-pointer. This can
result in a small performance penalty, as it effectively reduces the number of
general purpose registers available by one. (I'm also curious if this has
anything to do with the overly frequent "<value optimized out>" messages from
gdb.) If this shows up as a problem, we can make release builds still have
-fomit-frame-pointer, and fall back to backtrace when it's enabled then as
well.
This adds the fdbcli commands:
* profile list -- Lists all workers in a way that doesn't fill `kill`'s list.
* profile flow run -- Allows starting flow profiling on a set of hosts for a specified interval.
And threads through all the support for enabling and disabling profiling as an RPC.
Stephen Atherton