Kernel+LibC: Add support for filtering profiling events

This adds the -t command-line argument for the profile tool. Using this argument you can filter which event types you want in your profile.
Cnidarias · May 19, 2021 · 572bbf2 · 572bbf2
1 parent 8b2ace0
commit 572bbf2
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Showing 10 changed files with 72 additions and 33 deletions.
diff --git a/Kernel/PerformanceEventBuffer.cpp b/Kernel/PerformanceEventBuffer.cpp
@@ -60,6 +60,9 @@ KResult PerformanceEventBuffer::append_with_eip_and_ebp(ProcessID pid, ThreadID
  if (count() >= capacity())
  return ENOBUFS;
 
+ if ((g_profiling_event_mask & type) == 0)
+ return EINVAL;
+
  PerformanceEvent event;
  event.type = type;
  event.lost_samples = lost_samples;

diff --git a/Kernel/PerformanceEventBuffer.h b/Kernel/PerformanceEventBuffer.h
@@ -53,7 +53,7 @@ struct [[gnu::packed]] ContextSwitchPerformanceEvent {
 };
 
 struct [[gnu::packed]] PerformanceEvent {
- u8 type { 0 };
+ u16 type { 0 };
  u8 stack_size { 0 };
  u32 pid { 0 };
  u32 tid { 0 };
@@ -116,5 +116,6 @@ class PerformanceEventBuffer {
 
 extern bool g_profiling_all_threads;
 extern PerformanceEventBuffer* g_global_perf_events;
+extern u64 g_profiling_event_mask;
 
 }
diff --git a/Kernel/Process.h b/Kernel/Process.h
@@ -392,7 +392,7 @@ class Process
  KResultOr<int> sys$setkeymap(Userspace<const Syscall::SC_setkeymap_params*>);
  KResultOr<int> sys$module_load(Userspace<const char*> path, size_t path_length);
  KResultOr<int> sys$module_unload(Userspace<const char*> name, size_t name_length);
- KResultOr<int> sys$profiling_enable(pid_t);
+ KResultOr<int> sys$profiling_enable(pid_t, u64);
  KResultOr<int> sys$profiling_disable(pid_t);
  KResultOr<int> sys$profiling_free_buffer(pid_t);
  KResultOr<int> sys$futex(Userspace<const Syscall::SC_futex_params*>);

diff --git a/Kernel/Syscalls/profiling.cpp b/Kernel/Syscalls/profiling.cpp
@@ -15,15 +15,17 @@ namespace Kernel {
 
 bool g_profiling_all_threads;
 PerformanceEventBuffer* g_global_perf_events;
+u64 g_profiling_event_mask;
 
-KResultOr<int> Process::sys$profiling_enable(pid_t pid)
+KResultOr<int> Process::sys$profiling_enable(pid_t pid, u64 event_mask)
 {
  REQUIRE_NO_PROMISES;
 
  if (pid == -1) {
  if (!is_superuser())
  return EPERM;
  ScopedCritical critical;
+ g_profiling_event_mask = event_mask;
  if (g_global_perf_events)
  g_global_perf_events->clear();
  else
@@ -33,6 +35,7 @@ KResultOr<int> Process::sys$profiling_enable(pid_t pid)
  if (!TimeManagement::the().enable_profile_timer())
  return ENOTSUP;
  g_profiling_all_threads = true;
+ PerformanceManager::add_process_created_event(*Scheduler::colonel());
  Process::for_each([](auto& process) {
  PerformanceManager::add_process_created_event(process);
  return IterationDecision::Continue;
@@ -52,6 +55,7 @@ KResultOr<int> Process::sys$profiling_enable(pid_t pid)
  return ENOMEM;
  if (!TimeManagement::the().enable_profile_timer())
  return ENOTSUP;
+ g_profiling_event_mask = event_mask;
  process->set_profiling(true);
  return 0;
 }

diff --git a/Kernel/UnixTypes.h b/Kernel/UnixTypes.h
@@ -47,17 +47,17 @@ enum {
 };
 
 enum {
- PERF_EVENT_SAMPLE,
- PERF_EVENT_MALLOC,
- PERF_EVENT_FREE,
- PERF_EVENT_MMAP,
- PERF_EVENT_MUNMAP,
- PERF_EVENT_PROCESS_CREATE,
- PERF_EVENT_PROCESS_EXEC,
- PERF_EVENT_PROCESS_EXIT,
- PERF_EVENT_THREAD_CREATE,
- PERF_EVENT_THREAD_EXIT,
- PERF_EVENT_CONTEXT_SWITCH,
+ PERF_EVENT_SAMPLE = 1,
+ PERF_EVENT_MALLOC = 2,
+ PERF_EVENT_FREE = 4,
+ PERF_EVENT_MMAP = 8,
+ PERF_EVENT_MUNMAP = 16,
+ PERF_EVENT_PROCESS_CREATE = 32,
+ PERF_EVENT_PROCESS_EXEC = 64,
+ PERF_EVENT_PROCESS_EXIT = 128,
+ PERF_EVENT_THREAD_CREATE = 256,
+ PERF_EVENT_THREAD_EXIT = 512,
+ PERF_EVENT_CONTEXT_SWITCH = 1024,
 };
 
 #define WNOHANG 1

diff --git a/Kernel/init.cpp b/Kernel/init.cpp
@@ -287,7 +287,7 @@ void init_stage2(void*)
 
  if (boot_profiling) {
  dbgln("Starting full system boot profiling");
- auto result = Process::current()->sys$profiling_enable(-1);
+ auto result = Process::current()->sys$profiling_enable(-1, ~0ull);
  VERIFY(!result.is_error());
  }
 

diff --git a/Userland/DevTools/Profiler/main.cpp b/Userland/DevTools/Profiler/main.cpp
@@ -280,7 +280,7 @@ bool generate_profile(pid_t& pid)
  process_name = "(unknown)";
  }
 
- if (profiling_enable(pid) < 0) {
+ if (profiling_enable(pid, PERF_EVENT_MASK_ALL) < 0) {
  int saved_errno = errno;
  GUI::MessageBox::show(nullptr, String::formatted("Unable to profile process {}({}): {}", process_name, pid, strerror(saved_errno)), "Profiler", GUI::MessageBox::Type::Error);
  return false;

diff --git a/Userland/Libraries/LibC/serenity.cpp b/Userland/Libraries/LibC/serenity.cpp
@@ -30,9 +30,9 @@ int module_unload(const char* name, size_t name_length)
  __RETURN_WITH_ERRNO(rc, rc, -1);
 }
 
-int profiling_enable(pid_t pid)
+int profiling_enable(pid_t pid, uint64_t event_mask)
 {
- int rc = syscall(SC_profiling_enable, pid);
+ int rc = syscall(SC_profiling_enable, pid, event_mask);
  __RETURN_WITH_ERRNO(rc, rc, -1);
 }
 

diff --git a/Userland/Libraries/LibC/serenity.h b/Userland/Libraries/LibC/serenity.h
@@ -17,7 +17,7 @@ int disown(pid_t);
 int module_load(const char* path, size_t path_length);
 int module_unload(const char* name, size_t name_length);
 
-int profiling_enable(pid_t);
+int profiling_enable(pid_t, uint64_t);
 int profiling_disable(pid_t);
 int profiling_free_buffer(pid_t);
 
@@ -76,19 +76,21 @@ int futex(uint32_t* userspace_address, int futex_op, uint32_t value, const struc
 int purge(int mode);
 
 enum {
- PERF_EVENT_SAMPLE,
- PERF_EVENT_MALLOC,
- PERF_EVENT_FREE,
- PERF_EVENT_MMAP,
- PERF_EVENT_MUNMAP,
- PERF_EVENT_PROCESS_CREATE,
- PERF_EVENT_PROCESS_EXEC,
- PERF_EVENT_PROCESS_EXIT,
- PERF_EVENT_THREAD_CREATE,
- PERF_EVENT_THREAD_EXIT,
- PERF_EVENT_CONTEXT_SWITCH,
+ PERF_EVENT_SAMPLE = 1,
+ PERF_EVENT_MALLOC = 2,
+ PERF_EVENT_FREE = 4,
+ PERF_EVENT_MMAP = 8,
+ PERF_EVENT_MUNMAP = 16,
+ PERF_EVENT_PROCESS_CREATE = 32,
+ PERF_EVENT_PROCESS_EXEC = 64,
+ PERF_EVENT_PROCESS_EXIT = 128,
+ PERF_EVENT_THREAD_CREATE = 256,
+ PERF_EVENT_THREAD_EXIT = 512,
+ PERF_EVENT_CONTEXT_SWITCH = 1024,
 };
 
+#define PERF_EVENT_MASK_ALL (~0ull)
+
 int perf_event(int type, uintptr_t arg1, uintptr_t arg2);
 
 int get_stack_bounds(uintptr_t* user_stack_base, size_t* user_stack_size);

diff --git a/Userland/Utilities/profile.cpp b/Userland/Utilities/profile.cpp
@@ -21,6 +21,9 @@ int main(int argc, char** argv)
  bool enable = false;
  bool disable = false;
  bool all_processes = false;
+ u64 event_mask = PERF_EVENT_MMAP | PERF_EVENT_MUNMAP | PERF_EVENT_PROCESS_CREATE
+ | PERF_EVENT_PROCESS_EXEC | PERF_EVENT_PROCESS_EXIT | PERF_EVENT_THREAD_CREATE | PERF_EVENT_THREAD_EXIT;
+ bool seen_event_type_arg = false;
 
  args_parser.add_option(pid_argument, "Target PID", nullptr, 'p', "PID");
  args_parser.add_option(all_processes, "Profile all processes (super-user only)", nullptr, 'a');
@@ -29,14 +32,40 @@ int main(int argc, char** argv)
  args_parser.add_option(free, "Free the profiling buffer for the associated process(es).", nullptr, 'f');
  args_parser.add_option(wait, "Enable profiling and wait for user input to disable.", nullptr, 'w');
  args_parser.add_option(cmd_argument, "Command", nullptr, 'c', "command");
+ args_parser.add_option(Core::ArgsParser::Option {
+ true, "Enable tracking specific event type", nullptr, 't', "event_type",
+ [&](String event_type) {
+ seen_event_type_arg = true;
+ if (event_type == "sample")
+ event_mask |= PERF_EVENT_SAMPLE;
+ else if (event_type == "context_switch")
+ event_mask |= PERF_EVENT_CONTEXT_SWITCH;
+ else {
+ warnln("Unknown event type '{}' specified.", event_type);
+ exit(1);
+ }
+ return true;
+ } });
+
+ auto print_types = [] {
+ outln();
+ outln("Event type can be one of: sample and context_switch.");
+ };
 
- args_parser.parse(argc, argv);
+ if (!args_parser.parse(argc, argv, false)) {
+ print_types();
+ exit(1);
+ }
 
  if (!pid_argument && !cmd_argument && !all_processes) {
  args_parser.print_usage(stdout, argv[0]);
+ print_types();
  return 0;
  }
 
+ if (!seen_event_type_arg)
+ event_mask |= PERF_EVENT_SAMPLE;
+
  if (pid_argument || all_processes) {
  if (!(enable ^ disable ^ wait ^ free)) {
  fprintf(stderr, "-p <PID> requires -e xor -d xor -w xor -f.\n");
@@ -46,7 +75,7 @@ int main(int argc, char** argv)
  pid_t pid = all_processes ? -1 : atoi(pid_argument);
 
  if (wait || enable) {
- if (profiling_enable(pid) < 0) {
+ if (profiling_enable(pid, event_mask) < 0) {
  perror("profiling_enable");
  return 1;
  }
@@ -85,7 +114,7 @@ int main(int argc, char** argv)
  cmd_argv.append(nullptr);
 
  dbgln("Enabling profiling for PID {}", getpid());
- profiling_enable(getpid());
+ profiling_enable(getpid(), event_mask);
  if (execvp(cmd_argv[0], const_cast<char**>(cmd_argv.data())) < 0) {
  perror("execv");
  return 1;