Exclude threads test from rr tracing

src/jlapi.c

@@ -663,6 +663,17 @@ static void lock_low32(void)
 // Actual definition in `ast.c`
 void jl_lisp_prompt(void);
 
+static void rr_detach_teleport(void) {
+#ifdef _OS_LINUX_
+#define RR_CALL_BASE 1000
+#define SYS_rrcall_detach_teleport (RR_CALL_BASE + 9)
+ int err = syscall(SYS_rrcall_detach_teleport, 0, 0, 0, 0, 0, 0);
+ if (err < 0 || jl_running_under_rr(1)) {
+ jl_error("Failed to detach from rr session");
+ }
+#endif
+}
+
 JL_DLLEXPORT int repl_entrypoint(int argc, char *argv[])
 {
  // no-op on Windows, note that the caller must have already converted
@@ -678,7 +689,19 @@ JL_DLLEXPORT int repl_entrypoint(int argc, char *argv[])
  memmove(&argv[1], &argv[2], (argc-2)*sizeof(void*));
  argc--;
  }
+ char **orig_argv = argv;
  jl_parse_opts(&argc, (char***)&argv);
+
+ // The parent process requested that we detach from the rr session.
+ // N.B.: In a perfect world, we would only do this for the portion of
+ // the execution where we actually need to exclude rr (e.g. because we're
+ // testing for the absence of a memory-model-dependent bug).
+ if (jl_options.rr_detach && jl_running_under_rr(0)) {
+ rr_detach_teleport();
+ execv("/proc/self/exe", orig_argv);
+ jl_error("Failed to self-execute");
+ }
+
  julia_init(jl_options.image_file_specified ? JL_IMAGE_CWD : JL_IMAGE_JULIA_HOME);
  if (lisp_prompt) {
  jl_get_ptls_states()->world_age = jl_get_world_counter();

src/jloptions.c

@@ -75,6 +75,7 @@ jl_options_t jl_options = { 0, // quiet
  0, // image_file_specified
  JL_OPTIONS_WARN_SCOPE_ON, // ambiguous scope warning
  0, // image-codegen
+ 0, // rr-detach
 };
 
 static const char usage[] = "julia [switches] -- [programfile] [args...]\n";
@@ -203,6 +204,7 @@ JL_DLLEXPORT void jl_parse_opts(int *argcp, char ***argvp)
  opt_project,
  opt_bug_report,
  opt_image_codegen,
+ opt_rr_detach,
  };
  static const char* const shortopts = "+vhqH:e:E:L:J:C:it:p:O:g:";
  static const struct option longopts[] = {
@@ -254,6 +256,7 @@ JL_DLLEXPORT void jl_parse_opts(int *argcp, char ***argvp)
  { "bind-to", required_argument, 0, opt_bind_to },
  { "lisp", no_argument, 0, 1 },
  { "image-codegen", no_argument, 0, opt_image_codegen },
+ { "rr-detach", no_argument, 0, opt_rr_detach },
  { 0, 0, 0, 0 }
  };
 
@@ -655,6 +658,9 @@ JL_DLLEXPORT void jl_parse_opts(int *argcp, char ***argvp)
  case opt_image_codegen:
  jl_options.image_codegen = 1;
  break;
+ case opt_rr_detach:
+ jl_options.rr_detach = 1;
+ break;
  default:
  jl_errorf("julia: unhandled option -- %c\n"
  "This is a bug, please report it.", c);

src/julia.h

@@ -1947,6 +1947,7 @@ typedef struct {
  int8_t image_file_specified;
  int8_t warn_scope;
  int8_t image_codegen;
+ int8_t rr_detach;
 } jl_options_t;
 
 extern JL_DLLEXPORT jl_options_t jl_options;

src/julia_internal.h

@@ -83,6 +83,8 @@ void JL_UV_LOCK(void);
 extern "C" {
 #endif
 
+int jl_running_under_rr(int recheck);
+
 //--------------------------------------------------
 // timers
 // Returns time in nanosec

src/partr.c

@@ -274,14 +274,14 @@ JL_DLLEXPORT int jl_enqueue_task(jl_task_t *task)
 }
 
 
-static int running_under_rr(void)
+int jl_running_under_rr(int recheck)
 {
 #ifdef _OS_LINUX_
 #define RR_CALL_BASE 1000
 #define SYS_rrcall_check_presence (RR_CALL_BASE + 8)
  static int checked_running_under_rr = 0;
  static int is_running_under_rr = 0;
- if (!checked_running_under_rr) {
+ if (!checked_running_under_rr || recheck) {
  int ret = syscall(SYS_rrcall_check_presence, 0, 0, 0, 0, 0, 0);
  if (ret == -1) {
  // Should always be ENOSYS, but who knows what people do for
@@ -311,7 +311,7 @@ static int sleep_check_after_threshold(uint64_t *start_cycles)
  * scheduling logic from switching to other threads. Just don't bother
  * trying to wait here
  */
- if (running_under_rr())
+ if (jl_running_under_rr(0))
  return 1;
  if (!(*start_cycles)) {
  *start_cycles = jl_hrtime();

test/threads.jl

@@ -2,7 +2,7 @@
 
 using Test
 
-let cmd = `$(Base.julia_cmd()) --depwarn=error --startup-file=no threads_exec.jl`
+let cmd = `$(Base.julia_cmd()) --depwarn=error --rr-detach --startup-file=no threads_exec.jl`
  for test_nthreads in (1, 2, 4, 4) # run once to try single-threaded mode, then try a couple times to trigger bad races
  new_env = copy(ENV)
  new_env["JULIA_NUM_THREADS"] = string(test_nthreads)
@@ -11,12 +11,12 @@ let cmd = `$(Base.julia_cmd()) --depwarn=error --startup-file=no threads_exec.jl
 end
 
 # issue #34415 - make sure external affinity settings work
+const SYS_rrcall_check_presence = 1008
+running_under_rr() = 0 == ccall(:syscall, Int,
+ (Int, Int, Int, Int, Int, Int, Int),
+ SYS_rrcall_check_presence, 0, 0, 0, 0, 0, 0)
 
 if Sys.islinux()
- const SYS_rrcall_check_presence = 1008
- running_under_rr() = 0 == ccall(:syscall, Int,
- (Int, Int, Int, Int, Int, Int, Int),
- SYS_rrcall_check_presence, 0, 0, 0, 0, 0, 0)
  if Sys.CPU_THREADS > 1 && Sys.which("taskset") !== nothing && !running_under_rr()
  run_with_affinity(spec) = readchomp(`taskset -c $spec $(Base.julia_cmd()) -e "run(\`taskset -p \$(getpid())\`)"`)
  @test endswith(run_with_affinity("1"), "2")