This is like sample but has an "enter/exit" flag with it. This can be
useful when you want to provide tracing instead of sampling. We use a
different frame type so that we can denote that this isn't traditional
sampling, and the flag can be used to find the next exit for the current
enter for calculating durations.
The entire stack trace is provided to make things easier on tools
which may want to deal with indirect functions that were not instrumented
but can be unwound. That may allow for tooling to give the user some
insight that it's not *just* this function entering, but some functions
before it were entered too.
This also adds a SysprofTracer instrument which will preload a
libsysprof-tracer-6.so into the process providing the
__cyg_profile_func_enter() and __cyg_profile_func_leave() hooks.
These are just like `sysprof_collector_mark()`, but do the printf
formatting of the message internally, and only once the collector has
been fetched — so there is no overhead from the printf if sysprof is not
enabled at runtime.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
This is an almost entirely mechanical* conversion from (for example)
`gint` → `int`, `guint8` → `uint8_t`, etc.
It is not entirely complete, as many GLib functions are still used in
libsysprof-capture, which necessitate some use of GLib types.
It also avoids renaming `gboolean` → `bool` as that’s a slightly more
controversial change which will happen in the following commit.
*Code was manually realigned afterwards.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Helps: #40
This is a convenience function to call sysprof_collector_log() while also
formatting the message.
Ideally we'd be able to avoid the string format if we are not currently
collecting data, but that can be left for a future commit. We don't have
recursive locks so we need to duplicate the structure setup.
This is a simplified API for the inferior to use (such as from a
LD_PRELOAD) that will use mmap()'d ring buffer created by Sysprof. Doing
so can reduce the amount of overhead in the inferior enough to make some
workloads useful. For example, collecting memory statistics and backtraces
is now fast enough to be useful.
