Add monitor utility.

This commit is contained in:
Bartosz Taudul
2026-03-31 01:28:20 +02:00
parent 850cfd90f7
commit a0b3a71212
2 changed files with 368 additions and 0 deletions

44
monitor/CMakeLists.txt Normal file
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cmake_minimum_required(VERSION 3.16)
set(TRACY_PUBLIC_DIR ${CMAKE_CURRENT_LIST_DIR}/../public)
option(NO_ISA_EXTENSIONS "Disable ISA extensions (don't pass -march=native or -mcpu=native to the compiler)" OFF)
include(${CMAKE_CURRENT_LIST_DIR}/../cmake/version.cmake)
set(CMAKE_CXX_STANDARD 17)
project(
tracy-monitor
LANGUAGES C CXX
VERSION ${TRACY_VERSION_STRING}
)
find_package(Threads REQUIRED)
include(${CMAKE_CURRENT_LIST_DIR}/../cmake/config.cmake)
include(${CMAKE_CURRENT_LIST_DIR}/../cmake/vendor.cmake)
include(${CMAKE_CURRENT_LIST_DIR}/../cmake/GitRef.cmake)
set(PROGRAM_FILES
src/monitor.cpp
)
add_executable(${PROJECT_NAME} ${PROGRAM_FILES} ${TRACY_PUBLIC_DIR}/TracyClient.cpp)
target_include_directories(${PROJECT_NAME} SYSTEM PUBLIC
$<BUILD_INTERFACE:${TRACY_PUBLIC_DIR}>
$<INSTALL_INTERFACE:include/tracy>)
target_compile_definitions(${PROJECT_NAME} PRIVATE
TRACY_ENABLE
TRACY_DELAYED_INIT
TRACY_MANUAL_LIFETIME
TRACY_NO_FRAME_IMAGE
)
target_link_libraries(${PROJECT_NAME} PRIVATE
Threads::Threads
${CMAKE_DL_LIBS}
)
add_git_ref(${PROJECT_NAME})
install(TARGETS ${PROJECT_NAME} DESTINATION ${CMAKE_INSTALL_BINDIR})

324
monitor/src/monitor.cpp Normal file
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#include <errno.h>
#include <getopt.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/ptrace.h>
#include <sys/wait.h>
#include <unistd.h>
#include "../public/tracy/Tracy.hpp"
#include "../public/common/TracyVersion.hpp"
#include "../public/client/TracyCallstack.hpp"
#include "GitRef.hpp"
namespace tracy {
extern uint32_t ___tracy_magic_pid_override;
extern char ___tracy_magic_process_name[64];
}
static volatile sig_atomic_t s_shouldQuit = 0;
static pid_t s_targetPid = 0;
static bool s_isForked = false;
static void SignalHandler( int sig )
{
s_shouldQuit = 1;
}
static bool ReadProcessName( pid_t pid, char* buf, size_t bufSize )
{
char path[64];
snprintf( path, sizeof( path ), "/proc/%d/comm", (int)pid );
FILE* f = fopen( path, "r" );
if( !f ) return false;
if( !fgets( buf, bufSize, f ) )
{
fclose( f );
return false;
}
fclose( f );
// Remove trailing newline
size_t len = strlen( buf );
while( len > 0 && ( buf[len-1] == '\n' || buf[len-1] == '\r' ) ) len--;
buf[len] = '\0';
return len > 0;
}
static bool CheckPerfPermissions()
{
FILE* f = fopen( "/proc/sys/kernel/perf_event_paranoid", "r" );
if( !f )
{
fprintf( stderr, "Warning: Cannot read /proc/sys/kernel/perf_event_paranoid\n" );
return true; // Assume OK
}
int paranoid = 2;
if( fscanf( f, "%d", &paranoid ) != 1 ) paranoid = 2;
fclose( f );
if( paranoid > 1 && geteuid() != 0 )
{
fprintf( stderr, "Warning: perf_event_paranoid = %d. Profiling another process may require:\n", paranoid );
fprintf( stderr, " - Running as root, or\n" );
fprintf( stderr, " - Setting /proc/sys/kernel/perf_event_paranoid to -1 or 0, or\n" );
fprintf( stderr, " - Granting CAP_PERFMON + CAP_SYS_PTRACE capabilities\n" );
}
return true;
}
static bool ProcessIsAlive( pid_t pid )
{
return kill( pid, 0 ) == 0;
}
static void PrintUsage( const char* progName )
{
printf( "tracy-monitor %i.%i.%i / %s\n\n", tracy::Version::Major, tracy::Version::Minor, tracy::Version::Patch, tracy::GitRef );
printf( "Usage: %s [OPTIONS] program [arguments...]\n", progName );
printf( " %s [OPTIONS] -p PID\n", progName );
printf( "\n" );
printf( "Options:\n" );
printf( " -p PID Attach to existing process (PID)\n" );
printf( " -h Show this help message\n" );
printf( "\n" );
printf( "Examples:\n" );
printf( " %s ./my_program arg1 arg2\n", progName );
printf( " %s -p 1234\n", progName );
printf( "\n" );
printf( "The monitor captures sampling profiling data from an external process\n" );
printf( "and streams it to a Tracy server for visualization.\n" );
printf( "\n" );
printf( "In launch mode, the target program is started under ptrace control to\n" );
printf( "ensure profiling begins before the first instruction executes.\n" );
printf( "\n" );
printf( "In attach mode (-p), the target must already be running.\n" );
}
static int RunAttached( pid_t pid )
{
if( !ProcessIsAlive( pid ) )
{
fprintf( stderr, "Process %d does not exist or is not accessible.\n", (int)pid );
return 1;
}
s_targetPid = pid;
char procName[64];
if( ReadProcessName( pid, procName, sizeof( procName ) ) )
{
memcpy( tracy::___tracy_magic_process_name, procName, sizeof( tracy::___tracy_magic_process_name ) );
}
printf( "Attaching to process %d", (int)pid );
if( tracy::___tracy_magic_process_name[0] ) printf( " (%s)", tracy::___tracy_magic_process_name );
printf( "...\n" );
tracy::InitExternalImageCache( pid );
tracy::___tracy_magic_pid_override = (uint32_t)pid;
tracy::StartupProfiler();
printf( "Profiling started. Waiting for Tracy server connection...\n" );
// Wait for the target process to exit, or for a signal
while( !s_shouldQuit && ProcessIsAlive( pid ) )
{
usleep( 100000 ); // 100ms poll
}
if( s_shouldQuit )
{
printf( "\nShutting down profiler...\n" );
}
else
{
printf( "Target process %d exited.\n", (int)pid );
}
tracy::ShutdownProfiler();
return 0;
}
static int RunForked( int argc, char** argv )
{
pid_t childPid = fork();
if( childPid < 0 )
{
fprintf( stderr, "Unable to fork: %s\n", strerror( errno ) );
return 2;
}
if( childPid == 0 )
{
// Child process: request ptrace stop at exec, then exec the target
if( ptrace( PTRACE_TRACEME, 0, nullptr, nullptr ) < 0 )
{
fprintf( stderr, "ptrace(TRACEME) failed: %s\n", strerror( errno ) );
_exit( 2 );
}
execvp( argv[0], argv );
fprintf( stderr, "Unable to exec '%s': %s\n", argv[0], strerror( errno ) );
_exit( 2 );
}
// Parent: wait for the child to stop at the exec boundary (SIGTRAP)
s_targetPid = childPid;
s_isForked = true;
int status;
if( waitpid( childPid, &status, 0 ) < 0 )
{
fprintf( stderr, "waitpid failed: %s\n", strerror( errno ) );
return 2;
}
if( !WIFSTOPPED( status ) )
{
fprintf( stderr, "Child process did not stop as expected (status=0x%x).\n", status );
return 2;
}
// The child has exec'd but is stopped. Its address space is now the target program.
// Read its process name and memory maps.
char procName[64];
if( ReadProcessName( childPid, procName, sizeof( procName ) ) )
{
memcpy( tracy::___tracy_magic_process_name, procName, sizeof( tracy::___tracy_magic_process_name ) );
}
printf( "Profiling '%s' (pid %d)...\n",
tracy::___tracy_magic_process_name[0] ? tracy::___tracy_magic_process_name : argv[0],
(int)childPid );
// Initialize the external image cache (target's /proc/pid/maps)
tracy::InitExternalImageCache( childPid );
// Set up the profiler to target the child
tracy::___tracy_magic_pid_override = (uint32_t)childPid;
tracy::StartupProfiler();
// Detach ptrace and let the child run
if( ptrace( PTRACE_DETACH, childPid, nullptr, nullptr ) < 0 )
{
fprintf( stderr, "Warning: ptrace(DETACH) failed: %s\n", strerror( errno ) );
// Not fatal -- the child might still run
}
printf( "Profiling started. Waiting for Tracy server connection...\n" );
// Wait for child to exit, or for a signal
for(;;)
{
if( s_shouldQuit ) break;
int wstatus;
pid_t ret = waitpid( childPid, &wstatus, WNOHANG );
if( ret > 0 )
{
if( WIFEXITED( wstatus ) )
{
printf( "Target process exited with status %d.\n", WEXITSTATUS( wstatus ) );
}
else if( WIFSIGNALED( wstatus ) )
{
printf( "Target process killed by signal %d.\n", WTERMSIG( wstatus ) );
}
break;
}
else if( ret < 0 && errno != EINTR )
{
// Child already gone
break;
}
usleep( 100000 );
}
if( s_shouldQuit && ProcessIsAlive( childPid ) )
{
printf( "\nForwarding signal to child and shutting down...\n" );
kill( childPid, SIGINT );
// Give it a moment to exit
usleep( 500000 );
if( ProcessIsAlive( childPid ) )
{
kill( childPid, SIGKILL );
waitpid( childPid, nullptr, 0 );
}
}
tracy::ShutdownProfiler();
return 0;
}
int main( int argc, char** argv )
{
auto progName = argv[0];
if( argc < 2 )
{
PrintUsage( progName );
return 1;
}
// Install signal handlers for graceful shutdown
struct sigaction sa = {};
sa.sa_handler = SignalHandler;
sigemptyset( &sa.sa_mask );
sa.sa_flags = 0;
sigaction( SIGINT, &sa, nullptr );
sigaction( SIGTERM, &sa, nullptr );
pid_t attachPid = 0;
bool wantAttach = false;
static struct option longOptions[] = {
{ "pid", required_argument, nullptr, 'p' },
{ "help", no_argument, nullptr, 'h' },
{ nullptr, 0, nullptr, 0 }
};
int c;
while( ( c = getopt_long( argc, argv, "+p:h", longOptions, nullptr ) ) != -1 )
{
switch( c )
{
case 'p':
attachPid = atoi( optarg );
wantAttach = true;
break;
case 'h':
PrintUsage( argv[0] );
return 0;
case '?':
fprintf( stderr, "Unknown option. Use -h for help.\n" );
return 1;
}
}
argv += optind;
argc -= optind;
CheckPerfPermissions();
if( wantAttach )
{
if( attachPid <= 0 )
{
fprintf( stderr, "Invalid PID specified.\n" );
return 1;
}
return RunAttached( attachPid );
}
if( argc < 1 )
{
PrintUsage( progName ); // argv[0] was shifted, use original
return 1;
}
return RunForked( argc, argv );
}