From b6b8de1758be800f170a15d7cf05fffc04619bb8 Mon Sep 17 00:00:00 2001 From: Ian Coolidge Date: Thu, 19 Oct 2017 14:50:26 -0700 Subject: reland: cpu_linux: Don't spam sched_getcpu failures on qemu __NR_getcpu isn't implemented on qemu, and for some reason sysconf(_SC_NPROCESSORS_ONLN) returns the number of processers of the host system, giving a false indication that there is more than one cpu for the qemu case. Expand the init_num_cpus sequence to also run sched_getcpu once, if GPR_MUSL_LIBC_COMPAT isn't defined. If that call isn't supported, initialize 'ncpus' to 1. Later, in gpr_cpu_current_cpu, use gpr_cpu_num_cores to avoid the system call in cases where we know it isn't supported, or if the ncpus is otherwise 1. --- src/core/lib/support/cpu_linux.cc | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'src/core/lib/support/cpu_linux.cc') diff --git a/src/core/lib/support/cpu_linux.cc b/src/core/lib/support/cpu_linux.cc index 2280668442..21b1a71dc9 100644 --- a/src/core/lib/support/cpu_linux.cc +++ b/src/core/lib/support/cpu_linux.cc @@ -36,6 +36,13 @@ static int ncpus = 0; static void init_num_cpus() { +#ifndef GPR_MUSL_LIBC_COMPAT + if (sched_getcpu() < 0) { + gpr_log(GPR_ERROR, "Error determining current CPU: %s\n", strerror(errno)); + ncpus = 1; + return; + } +#endif /* This must be signed. sysconf returns -1 when the number cannot be determined */ ncpus = (int)sysconf(_SC_NPROCESSORS_ONLN); @@ -56,6 +63,9 @@ unsigned gpr_cpu_current_cpu(void) { // sched_getcpu() is undefined on musl return 0; #else + if (gpr_cpu_num_cores() == 1) { + return 0; + } int cpu = sched_getcpu(); if (cpu < 0) { gpr_log(GPR_ERROR, "Error determining current CPU: %s\n", strerror(errno)); -- cgit v1.2.3