There are typically 0 or 1 conditions applied to a cursor, and they’re
only applied at construction time, so it makes sense to only grow the
conditions array linearly when it’s used. This means the array may stay
as `NULL` throughout the lifetime of the cursor.
There’s currently no way to return an error from
`sysprof_capture_cursor_add_condition()`, so an allocation failure
results in an abort.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Helps: #40
libsysprof-capture no longer calls any of the GLib logging functions
which make use of it.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Helps: #40
Another step away from GLib. This changes the OOM behaviour of the
library — previously it would immediately `abort()` on OOM. However, it
seems likely that given the small number of allocations
libsysprof-capture does, it should be able to recover from an OOM
situation more gracefully than larger libraries can — so the new
implementation tries to do that.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Helps: #40
Use the intrinsic atomics provided by the compiler, instead of GLib’s
wrapper around them. This should work for all modern compilers.
Signed-off-by: Philip Withnall <withnall@endlessm.com>
Helps: #40
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 brings over some of the techniques from the old memprof design.
Sysprof and memprof shared a lot of code, so it is pretty natural to
bring back the same callgraph view based on memory allocations.
This reuses the StackStash just like it did in memprof. While it
would be nice to reuse some existing tools out there, the fit of
memprof with sysprof is so naturally aligned, it's not really a
big deal to bring back the LD_PRELOAD. The value really comes
from seeing all this stuff together instead of multiple apps.
There are plenty of things we can implement on top of this that
we are not doing yet such as temporary allocations, cross-thread
frees, graphing the heap, and graphing differences between the
heap at to points in time. I'd like all of these things, given
enough time to make them useful.
This is still a bit slow though due to the global lock we take
to access the writer. To improve the speed here we need to get
rid of that lock and head towards a design that allows a thread
to request a new writer from Sysprof and save it in TLS (to be
destroyed when the thread exits).
This allows embedding the static capture library without having to deal
with license incompatibility while retaining the patent clause. We want
as many consumers of the format as makes sense without the restriction
of what kind of app/library/tooling they are.
The application, sysprofd, libsysprof, and libsysprof-ui continue to be
GPLv3+.
As we gain in usage, we need to be more careful about using a prefix
that will not collide with other symbols. So version 3 of our ABI will
change to using Sysprof/SYSPROF/sysprof as the various prefixes.
The soname/api version bump will happen later on this branch so that
things are easier to test up until then.
