From 49d0abc5c80d6ed49eb1ba019cc95d44bf0f5029 Mon Sep 17 00:00:00 2001 From: Richard Purdie Date: Fri, 18 Jul 2025 13:56:54 +0100 Subject: bitbake: utils: Optimise signal/sigmask performance Running "time bitbake -pP idle" with a valid cache shows around 800,000 calls to enum creation from python's signal.py. We don't care about this overhead and it adversely affects cache load time quite badly. Try and use _signal directly, falling back to signal, which avoids this overhead we don't need and makes cache loading much faster. (Bitbake rev: ee5fce67ce35b025c68aa61e2e758903269ee346) Signed-off-by: Richard Purdie --- bitbake/lib/bb/utils.py | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) (limited to 'bitbake/lib/bb/utils.py') diff --git a/bitbake/lib/bb/utils.py b/bitbake/lib/bb/utils.py index f688f7dd68..016036dbce 100644 --- a/bitbake/lib/bb/utils.py +++ b/bitbake/lib/bb/utils.py @@ -2226,6 +2226,15 @@ def path_is_descendant(descendant, ancestor): return False +# Recomputing the sets in signal.py is expensive (bitbake -pP idle) +# so try and use _signal directly to avoid it +valid_signals = signal.valid_signals() +try: + import _signal + sigmask = _signal.pthread_sigmask +except ImportError: + sigmask = signal.pthread_sigmask + # If we don't have a timeout of some kind and a process/thread exits badly (for example # OOM killed) and held a lock, we'd just hang in the lock futex forever. It is better # we exit at some point than hang. 5 minutes with no progress means we're probably deadlocked. @@ -2235,7 +2244,7 @@ def path_is_descendant(descendant, ancestor): @contextmanager def lock_timeout(lock): try: - s = signal.pthread_sigmask(signal.SIG_BLOCK, signal.valid_signals()) + s = sigmask(signal.SIG_BLOCK, valid_signals) held = lock.acquire(timeout=5*60) if not held: bb.server.process.serverlog("Couldn't get the lock for 5 mins, timed out, exiting.\n%s" % traceback.format_stack()) @@ -2243,17 +2252,17 @@ def lock_timeout(lock): yield held finally: lock.release() - signal.pthread_sigmask(signal.SIG_SETMASK, s) + sigmask(signal.SIG_SETMASK, s) # A version of lock_timeout without the check that the lock was locked and a shorter timeout @contextmanager def lock_timeout_nocheck(lock): l = False try: - s = signal.pthread_sigmask(signal.SIG_BLOCK, signal.valid_signals()) + s = sigmask(signal.SIG_BLOCK, valid_signals) l = lock.acquire(timeout=10) yield l finally: if l: lock.release() - signal.pthread_sigmask(signal.SIG_SETMASK, s) + sigmask(signal.SIG_SETMASK, s) -- cgit v1.2.3-54-g00ecf