runtime: on 32-bit systems, limit default GOMAXPROCS to 32
Otherwise we can easily run out of stack space for threads.
The user can still override by setting GOMAXPROCS.
Change-Id: I30cebf1d08434f55c44c44ed9894e3e507665d35
Reviewed-on: https://go-review.googlesource.com/c/gofrontend/+/219278
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Cherry Zhang <cherryyz@google.com>
diff --git a/libgo/go/runtime/proc.go b/libgo/go/runtime/proc.go
index c0e8577..e3f934a 100644
--- a/libgo/go/runtime/proc.go
+++ b/libgo/go/runtime/proc.go
@@ -563,6 +563,14 @@
sched.lastpoll = uint64(nanotime())
procs := ncpu
+
+ // In 32-bit mode, we can burn a lot of memory on thread stacks.
+ // Try to avoid this by limiting the number of threads we run
+ // by default.
+ if sys.PtrSize == 4 && procs > 32 {
+ procs = 32
+ }
+
if n, ok := atoi32(gogetenv("GOMAXPROCS")); ok && n > 0 {
procs = n
}
