The traced top instance was configured to be active every two seconds
whereas the trace test uses a grace time of only 1.5 seconds before
raising the FOREIGN state of a trace subject as an error.
The state of a trace subject can change only whenever the traced thread
passes a trace point. Hence, with the original configuration, the
release of top as trace subject can take up to two seconds. The patch
reduces the rate to 0.5 seconds to satisfy the expectation of
test-trace.
This patch changes core's TRACE service to expose trace subjects only if
their PD label matches the label of the TRACE monitor. Hence, by default,
a trace monitor can only observe itself and its child components. Only
if the trace monitor's parent rewrites the trace-session's label, the
view of trace monitor can become broader. For example, when rewriting
the trace label to an empty string "", the trace monitor becomes able to
observe the sibling components hosted in the same init instance as the
trace monitor.
To grant a trace session the special privilege of obtaining a global
system view (including the kernel's trace subjects), the top-level init
has to rewrite the session's label to an empty string. At core, this
specific label "init -> " is handled as a special case that discharges
the filtering/namespacing of trace subjects.
Note that the trace-subject label as reported as subject info is now
given relative to the label of the trace session. As a nice side effect
of this change, the pkg/test-trace_logger works now when executed by the
depot_autopilot as well as via the test.run script.
Issue #847
* Removes the <event> tag from all test package runtime files and replaces the
contained <timeout> and <log> sub-tags with the new tags <succeed> and
<fail>. If a <succeed> or <fail> tag has a content, it defines a log pattern
that should be recognized and render the test failed or successful. If a
<succeed> or <fail> tag has an attribute after_seconds that is not set to 0,
it defines a timeout after which the test should be rendered failed or
successful.
* Adapts the Depot Autopilot to support the new syntax in the test-package
runtime files. However, for now, the Depot Autopilot is kept compatible to
the old syntax as well. If the <events> tag is present, it is prioritized
over the new syntax.
Fixes#4922
If the trace subjects are not properly destructed when the TRACE client
disappears, enabled sources will be owned by a non-existing client.
In other words, when a TRACE client disappears all sources owned by the
client must be disabled.
genodelabs/genode#4247
