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authorRickard Green <[email protected]>2011-11-18 12:46:43 +0100
committerRickard Green <[email protected]>2011-11-18 13:09:16 +0100
commit58f5f45566b827e74ff623398bdf6d0b6fcebdb3 (patch)
tree3d68d4afef9e55d4453b8550ba2488d202a2b484 /erts/emulator
parenta8ecde4e398942260153d8b2f37344af259b1007 (diff)
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Use unbound schedulers as default
As of ERTS version 5.9 (OTP-R15B) the runtime system will by default not bind schedulers to logical processors. If the Erlang runtime system is the only operating system process that binds threads to logical processors, this improves the performance of the runtime system. However, if other operating system processes (as for example another Erlang runtime system) also bind threads to logical processors, there might be a performance penalty instead. In some cases this performance penalty might be severe. Due to this, we change the default so that the user must make an active decision in order to bind schedulers.
Diffstat (limited to 'erts/emulator')
-rw-r--r--erts/emulator/beam/erl_cpu_topology.c12
1 files changed, 2 insertions, 10 deletions
diff --git a/erts/emulator/beam/erl_cpu_topology.c b/erts/emulator/beam/erl_cpu_topology.c
index 03c0ef904a..cc930ba1e3 100644
--- a/erts/emulator/beam/erl_cpu_topology.c
+++ b/erts/emulator/beam/erl_cpu_topology.c
@@ -1729,16 +1729,8 @@ erts_init_cpu_topology(void)
scheduler2cpu_map[ix].bound_id = -1;
}
- if (cpu_bind_order == ERTS_CPU_BIND_UNDEFINED) {
- int ncpus = erts_get_cpu_configured(cpuinfo);
- if (ncpus < 1 || erts_no_schedulers < ncpus)
- cpu_bind_order = ERTS_CPU_BIND_NONE;
- else
- cpu_bind_order = ((system_cpudata || user_cpudata)
- && (erts_bind_to_cpu(cpuinfo, -1) != -ENOTSUP)
- ? ERTS_CPU_BIND_DEFAULT_BIND
- : ERTS_CPU_BIND_NONE);
- }
+ if (cpu_bind_order == ERTS_CPU_BIND_UNDEFINED)
+ cpu_bind_order = ERTS_CPU_BIND_NONE;
reader_groups_map = add_cpu_groups(reader_groups,
reader_groups_callback,