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 adds the common convention for applications that receive command
line arguments to use [-- COMMAND ARGS] instead of "-c" which is rather
limiting for shell expansion.
Fixes#10
We want the viewer to be usable on Mac/Windows/FreeBSD, even if our
profiler tooling isn't (yet).
Another option could be to do a simplified viewer window for those
platforms, but I think that is more work to maintain than abstracting
some of the stuff better in libsysprof.
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.
This moves everything into other places and simple includes the
files in the cases that it is necessary. In the future, we can
rewrite sysprofd to use GDBus and add GetProcFile() to allow
for client-side processing of kallsyms.
This doesn't make profiling useful in any way, but it does get things
to the point where I can actually open a capture file. And it would
be nice if we could progress to the point of loading capture files
(with correct data in-tact) and this helps us move down that path.
To really do that correctly, we should make some of the widgetry
disabled when it isn't useful. We also need to ensure that we add extra
decoding information to capture files during shutdown so that any
platform can read it back. This would also help the situation of
running and reading on separate architectures.
The big thing going on here is that we are going to split up the libraries
a bit better, and remove GObject from the capture library. The libsysprof
library will bring in the capture library statically, so we can export the
symbols we want.
Eventually, we will bump the version to sysprof-3, but not yet.
