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	 8614d18956
			
		
	
	
		8614d18956
		
	
	
	
	
		
			
			This updates the profiling subsystem to use a separate timer to trigger CPU sampling. This timer has a higher resolution (1000Hz) and is independent from the scheduler. At a later time the resolution could even be made configurable with an argument for sys$profiling_enable() - but not today.
		
			
				
	
	
		
			114 lines
		
	
	
	
		
			2.9 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
			
		
		
	
	
			114 lines
		
	
	
	
		
			2.9 KiB
		
	
	
	
		
			C++
		
	
	
	
	
	
| /*
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|  * Copyright (c) 2018-2021, Andreas Kling <kling@serenityos.org>
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|  *
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|  * SPDX-License-Identifier: BSD-2-Clause
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|  */
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| 
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| #include <Kernel/CoreDump.h>
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| #include <Kernel/FileSystem/FileDescription.h>
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| #include <Kernel/FileSystem/VirtualFileSystem.h>
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| #include <Kernel/PerformanceManager.h>
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| #include <Kernel/Process.h>
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| #include <Kernel/Time/TimeManagement.h>
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| 
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| namespace Kernel {
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| 
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| bool g_profiling_all_threads;
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| PerformanceEventBuffer* g_global_perf_events;
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| 
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| KResultOr<int> Process::sys$profiling_enable(pid_t pid)
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| {
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|     REQUIRE_NO_PROMISES;
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| 
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|     if (pid == -1) {
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|         if (!is_superuser())
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|             return EPERM;
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|         ScopedCritical critical;
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|         if (g_global_perf_events)
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|             g_global_perf_events->clear();
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|         else
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|             g_global_perf_events = PerformanceEventBuffer::try_create_with_size(32 * MiB).leak_ptr();
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| 
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|         ScopedSpinLock lock(g_processes_lock);
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|         g_profiling_all_threads = true;
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|         Process::for_each([](auto& process) {
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|             PerformanceManager::add_process_created_event(process);
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|             return IterationDecision::Continue;
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|         });
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|         TimeManagement::the().enable_profile_timer();
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|         return 0;
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|     }
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| 
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|     ScopedSpinLock lock(g_processes_lock);
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|     auto process = Process::from_pid(pid);
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|     if (!process)
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|         return ESRCH;
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|     if (process->is_dead())
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|         return ESRCH;
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|     if (!is_superuser() && process->uid() != euid())
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|         return EPERM;
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|     if (!process->create_perf_events_buffer_if_needed())
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|         return ENOMEM;
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|     process->set_profiling(true);
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|     TimeManagement::the().enable_profile_timer();
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|     return 0;
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| }
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| 
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| KResultOr<int> Process::sys$profiling_disable(pid_t pid)
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| {
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|     REQUIRE_NO_PROMISES;
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| 
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|     if (pid == -1) {
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|         if (!is_superuser())
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|             return EPERM;
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|         ScopedCritical critical;
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|         g_profiling_all_threads = false;
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|         TimeManagement::the().disable_profile_timer();
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|         return 0;
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|     }
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| 
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|     ScopedSpinLock lock(g_processes_lock);
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|     auto process = Process::from_pid(pid);
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|     if (!process)
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|         return ESRCH;
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|     if (!is_superuser() && process->uid() != euid())
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|         return EPERM;
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|     if (!process->is_profiling())
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|         return EINVAL;
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|     TimeManagement::the().disable_profile_timer();
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|     process->set_profiling(false);
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|     return 0;
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| }
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| 
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| KResultOr<int> Process::sys$profiling_free_buffer(pid_t pid)
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| {
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|     REQUIRE_NO_PROMISES;
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| 
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|     if (pid == -1) {
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|         if (!is_superuser())
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|             return EPERM;
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| 
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|         OwnPtr<PerformanceEventBuffer> perf_events;
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| 
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|         {
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|             ScopedCritical critical;
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| 
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|             perf_events = g_global_perf_events;
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|             g_global_perf_events = nullptr;
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|         }
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| 
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|         return 0;
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|     }
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| 
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|     ScopedSpinLock lock(g_processes_lock);
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|     auto process = Process::from_pid(pid);
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|     if (!process)
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|         return ESRCH;
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|     if (!is_superuser() && process->uid() != euid())
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|         return EPERM;
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|     if (process->is_profiling())
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|         return EINVAL;
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|     process->delete_perf_events_buffer();
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|     return 0;
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| }
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| }
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