genode/repos/base-pistachio/lib/mk/base-pistachio.mk

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include $(BASE_DIR)/lib/mk/base.inc
os/timer: interpolate time via timestamps Previously, the Genode::Timer::curr_time always used the Timer_session::elapsed_ms RPC as back end. Now, Genode::Timer reads this remote time only in a periodic fashion independently from the calls to Genode::Timer::curr_time. If now one calls Genode::Timer::curr_time, the function takes the last read remote time value and adapts it using the timestamp difference since the remote-time read. The conversion factor from timestamps to time is estimated on every remote-time read using the last read remote-time value and the timestamp difference since the last remote time read. This commit also re-works the timeout test. The test now has two stages. In the first stage, it tests fast polling of the Genode::Timer::curr_time. This stage checks the error between locally interpolated and timer-driver time as well as wether the locally interpolated time is monotone and sufficiently homogeneous. In the second stage several periodic and one-shot timeouts are scheduled at once. This stage checks if the timeouts trigger sufficiently precise. This commit adds the new Kernel::time syscall to base-hw. The syscall is solely used by the Genode::Timer on base-hw as substitute for the timestamp. This is because on ARM, the timestamp function uses the ARM performance counter that stops counting when the WFI (wait for interrupt) instruction is active. This instruction, however is used by the base-hw idle contexts that get active when no user thread needs to be scheduled. Thus, the ARM performance counter is not a good choice for time interpolation and we use the kernel internal time instead. With this commit, the timeout library becomes a basic library. That means that it is linked against the LDSO which then provides it to the program it serves. Furthermore, you can't use the timeout library anymore without the LDSO because through the kernel-dependent LDSO make-files we can achieve a kernel-dependent timeout implementation. This commit introduces a structured Duration type that shall successively replace the use of Microseconds, Milliseconds, and integer types for duration values. Open issues: * The timeout test fails on Raspberry PI because of precision errors in the first stage. However, this does not render the framework unusable in general on the RPI but merely is an issue when speaking of microseconds precision. * If we run on ARM with another Kernel than HW the timestamp speed may continuously vary from almost 0 up to CPU speed. The Timer, however, only uses interpolation if the timestamp speed remained stable (12.5% tolerance) for at least 3 observation periods. Currently, one period is 100ms, so its 300ms. As long as this is not the case, Timer_session::elapsed_ms is called instead. Anyway, it might happen that the CPU load was stable for some time so interpolation becomes active and now the timestamp speed drops. In the worst case, we would now have 100ms of slowed down time. The bad thing about it would be, that this also affects the timeout of the period. Thus, it might "freeze" the local time for more than 100ms. On the other hand, if the timestamp speed suddenly raises after some stable time, interpolated time can get too fast. This would shorten the period but nonetheless may result in drifting away into the far future. Now we would have the problem that we can't deliver the real time anymore until it has caught up because the output of Timer::curr_time shall be monotone. So, effectively local time might "freeze" again for more than 100ms. It would be a solution to not use the Trace::timestamp on ARM w/o HW but a function whose return value causes the Timer to never use interpolation because of its stability policy. Fixes #2400
2017-04-21 22:52:23 +00:00
LIBS += base-pistachio-common syscall-pistachio cxx timeout
Disambiguate kernel-specific file names This patch removes possible ambiguities with respect to the naming of kernel-dependent binaries and libraries. It also removes the use of kernel-specific global side effects from the build system. The reach of kernel-specific peculiarities has thereby become limited to the actual users of the respective 'syscall-<kernel>' libraries. Kernel-specific build artifacts are no longer generated at magic places within the build directory (like okl4's includes, or the L4 build directories of L4/Fiasco and Fiasco.OC, or the build directories of various kernels). Instead, such artifacts have been largely moved to the libcache. E.g., the former '<build-dir>/l4/' build directory for the L4 build system resides at '<build-dir>/var/libcache/syscall-foc/build/'. This way, the location is unique to the kernel. Note that various tools are still generated somewhat arbitrarily under '<build-dir>/tool/' as there is no proper formalism for building host tools yet. As the result of this work, it has become possible to use a joint Genode build directory that is usable with all kernels of a given hardware platform. E.g., on x86_32, one can now seamlessly switch between linux, nova, sel4, okl4, fiasco, foc, and pistachio without rebuilding any components except for core, the kernel, the dynamic linker, and the timer driver. At the current stage, such a build directory must still be created manually. A change of the 'create_builddir' tool will follow to make this feature easily available. This patch also simplifies various 'run/boot_dir' plugins by removing the option for an externally hosted kernel. This option remained unused for many years now. Issue #2190
2016-12-10 00:30:38 +00:00
SRC_CC += thread_start.cc
SRC_CC += cache.cc
SRC_CC += capability_slab.cc
SRC_CC += capability_space.cc
SRC_CC += signal_transmitter.cc
SRC_CC += signal.cc