8f9355b360
In the init configuration one can configure the donation of CPU time via 'resource' tags that have the attribute 'name' set to "CPU" and the attribute 'quantum' set to the percentage of CPU quota that init shall donate. The pattern is the same as when donating RAM quota. ! <start name="test"> ! <resource name="CPU" quantum="75"/> ! </start> This would cause init to try donating 75% of its CPU quota to the child "test". Init and core do not preserve CPU quota for their own requirements by default as it is done with RAM quota. The CPU quota that a process owns can be applied through the thread constructor. The constructor has been enhanced by an argument that indicates the percentage of the programs CPU quota that shall be granted to the new thread. So 'Thread(33, "test")' would cause the backing CPU session to try to grant 33% of the programs CPU quota to the thread "test". By now, the CPU quota of a thread can't be altered after construction. Constructing a thread with CPU quota 0 doesn't mean the thread gets never scheduled but that the thread has no guaranty to receive CPU time. Such threads have to live with excess CPU time. Threads that already existed in the official repositories of Genode were adapted in the way that they receive a quota of 0. This commit also provides a run test 'cpu_quota' in base-hw (the only kernel that applies the CPU-quota scheme currently). The test basically runs three threads with different physical CPU quota. The threads simply count for 30 seconds each and the test then checks wether the counter values relate to the CPU-quota distribution. fix #1275
97 lines
2.4 KiB
C++
97 lines
2.4 KiB
C++
/*
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* \brief Thread bootstrap code
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* \author Christian Prochaska
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* \author Martin Stein
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* \date 2013-02-15
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*/
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/*
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* Copyright (C) 2013 Genode Labs GmbH
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*
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* This file is part of the Genode OS framework, which is distributed
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* under the terms of the GNU General Public License version 2.
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*/
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/* Genode includes */
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#include <base/thread.h>
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#include <base/env.h>
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#include <util/string.h>
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/* Codezero includes */
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#include <codezero/syscalls.h>
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Genode::Native_thread_id main_thread_tid;
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Codezero::l4_mutex main_thread_running_lock;
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/*****************************
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** Startup library support **
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*****************************/
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void prepare_init_main_thread()
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{
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/* initialize codezero environment */
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Codezero::__l4_init();
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/* provide kernel identification of thread through temporary environment */
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main_thread_tid = Codezero::thread_myself();
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}
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void prepare_reinit_main_thread() { prepare_init_main_thread(); }
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/****************************
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** Codezero libl4 support **
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****************************/
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/*
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* Unfortunately, the function 'exregs_print_registers' in 'exregs.c' refers to
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* 'memset'. Because we do not want to link core against a C library, we have to
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* resolve this function here.
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*/
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extern "C" void *memset(void *s, int c, Genode::size_t n) __attribute__((weak));
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extern "C" void *memset(void *s, int c, Genode::size_t n)
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{
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return Genode::memset(s, c, n);
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}
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/*
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* Same problem as for 'memset'. The 'printf' symbol is referenced from
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* 'mutex.c' and 'exregs.c' of Codezero's libl4.
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*/
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extern "C" int printf(const char *format, ...) __attribute__((weak));
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extern "C" int printf(const char *format, ...)
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{
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va_list list;
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va_start(list, format);
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Genode::vprintf(format, list);
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va_end(list);
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return 0;
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}
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/*****************
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** Thread_base **
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*****************/
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void Genode::Thread_base::_thread_bootstrap()
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{
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Codezero::l4_mutex_init(utcb()->running_lock());
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Codezero::l4_mutex_lock(utcb()->running_lock()); /* block on first mutex lock */
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}
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void Genode::Thread_base::_init_platform_thread(size_t, Type type)
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{
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if (type == NORMAL) { return; }
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/* adjust values whose computation differs for a main thread */
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_tid.l4id = main_thread_tid;
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_thread_cap = Genode::env()->parent()->main_thread_cap();
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/* get first mutex lock (normally done by _thread_bootstrap) */
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Codezero::l4_mutex_init(utcb()->running_lock());
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Codezero::l4_mutex_lock(utcb()->running_lock());
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}
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