fix #34415, remove affinity setting code (#34433)

This was removed before and added back apparently by mistake.

(cherry picked from commit 5928786)

src/init.c

@@ -698,18 +698,6 @@ void _julia_init(JL_IMAGE_SEARCH rel)
     }
 #endif
 
-#if defined(__linux__)
-    int ncores = jl_cpu_threads();
-    if (ncores > 1) {
-        cpu_set_t cpumask;
-        CPU_ZERO(&cpumask);
-        for(int i=0; i < ncores; i++) {
-            CPU_SET(i, &cpumask);
-        }
-        sched_setaffinity(0, sizeof(cpu_set_t), &cpumask);
-    }
-#endif
-
     if ((jl_options.outputo || jl_options.outputbc) &&
         (jl_options.code_coverage || jl_options.malloc_log)) {
         jl_error("cannot generate code-coverage or track allocation information while generating a .o or .bc output file");

src/julia_internal.h

@@ -8,7 +8,6 @@
 #include <uv.h>
 #if !defined(_MSC_VER) && !defined(__MINGW32__)
 #include <unistd.h>
-#include <sched.h>
 #else
 #define sleep(x) Sleep(1000*x)
 #endif

test/threads.jl

@@ -13,3 +13,10 @@ let p, cmd = `$(Base.julia_cmd()) --depwarn=error --startup-file=no threads_exec
         error("threads test failed with nthreads == $other_nthreads")
     end
 end
+
+# issue #34415 - make sure external affinity settings work
+if Sys.islinux() && Sys.CPU_THREADS > 1 && Sys.which("taskset") !== nothing
+    run_with_affinity(spec) = readchomp(`taskset -c $spec $(Base.julia_cmd()) -e "run(\`taskset -p \$(getpid())\`)"`)
+    @test endswith(run_with_affinity("1"), "2")
+    @test endswith(run_with_affinity("0,1"), "3")
+end