From 19f290f223376cc9428a1b8fc08476dc76b578ee Mon Sep 17 00:00:00 2001 From: Richard Purdie Date: Wed, 22 Jul 2015 23:28:17 +0100 Subject: bitbake: data_smart: Add CoW approach for overridedata Using deepcopy() caused a major performance regression. Turns out we can work with a shallow copy as long as we force the recreation of any list that we change, effectively a poor mans CoW. This isn't too invasive and avoids the huge overhead of deepcopy so this seems like the best way to have performance and a working data store. (Bitbake rev: 32dff4749c32f32e947c42c86f8357b8b607354b) Signed-off-by: Richard Purdie --- bitbake/lib/bb/data_smart.py | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'bitbake/lib/bb/data_smart.py') diff --git a/bitbake/lib/bb/data_smart.py b/bitbake/lib/bb/data_smart.py index e69f8d72df..a7cae77d36 100644 --- a/bitbake/lib/bb/data_smart.py +++ b/bitbake/lib/bb/data_smart.py @@ -310,6 +310,9 @@ class DataSmart(MutableMapping): self.expand_cache = {} # cookie monster tribute + # Need to be careful about writes to overridedata as + # its only a shallow copy, could influence other data store + # copies! self.overridedata = {} self.overrides = None self.overridevars = set(["OVERRIDES", "FILE"]) @@ -481,6 +484,8 @@ class DataSmart(MutableMapping): if shortvar not in self.overridedata: self.overridedata[shortvar] = [] if [var, override] not in self.overridedata[shortvar]: + # Force CoW by recreating the list first + self.overridedata[shortvar] = list(self.overridedata[shortvar]) self.overridedata[shortvar].append([var, override]) for event in self.varhistory.variable(var): if 'flag' in loginfo and not loginfo['flag'].startswith("_"): @@ -561,6 +566,8 @@ class DataSmart(MutableMapping): while override: try: if shortvar in self.overridedata: + # Force CoW by recreating the list first + self.overridedata[shortvar] = list(self.overridedata[shortvar]) self.overridedata[shortvar].remove([var, override]) except ValueError as e: pass @@ -780,7 +787,9 @@ class DataSmart(MutableMapping): data.overrides = None data.overridevars = copy.copy(self.overridevars) - data.overridedata = copy.deepcopy(self.overridedata) + # Should really be a deepcopy but has heavy overhead. + # Instead, we're careful with writes. + data.overridedata = copy.copy(self.overridedata) return data -- cgit v1.2.3-54-g00ecf