This tells the SysprofProfiler that it should avoid using sysprofd unless
for some reason that instrument simply cannot work without it. Currently
that is at least the RAPL and user-space stack decoding instruments
but there may be others.
If this property is set to TRUE (the default) it queries sysprofd and
policy-kit for appropriate privileges. That generally means that the
instruments will use sysprofd to get access to things like /proc files,
perf event streams, and what not.
If set to FALSE, then this tells the instruments that they should try to
do that work locally instead of querying the sysprofd instance via D-Bus.
If we were provided a D-Bus connection to use for sysprofd then use that.
Otherwise, try to fallback to doing the work in process without the help
of sysprofd.
If we are setup without a D-Bus connection to use to talk to sysprofd then
try to perform the syscall() directly for perf_event_open.
Generally that means you need to be root.
This is used to tell the instruments what GDBusConnection they should use
to query sysprofd. Lack of a connection means they should try to do things
in process without querying sysprofd.
This helper allows us to get the file locally or via sysprofd when the
GDBusConnection is provided.
Be careful about use as your local /proc may be different than the
"system" /proc where sysprofd lives.
In map_head_and_body_twice(), the second mmap call fails:
mmap2(NULL, 135168, PROT_READ|PROT_WRITE, MAP_SHARED, 3, 0) = 0xf64a2000
mmap2(0xf64b3000, 65536, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_FIXED, 3, 0x1000) = -1 EINVAL (Invalid argument)
Due to cache issues, all shared mapping of a page must be equivalently
mapped. This requires page mappings to be at the same virtual address
modulo 4 MB. Due to a kernel limitation, all mappings to a file must
be equivalent.
The test can be fixed by rounding the buffer_size used in the mapped
ring buffer to 4 MB on hppa. This makes the two mmap mappings equivalent.
Bug-Debian: https://bugs.debian.org/1021853
