From 7c871163c8803e812998e5b2296e3bbb30b1367f Mon Sep 17 00:00:00 2001 From: Mike Frysinger Date: Tue, 16 Feb 2021 01:45:39 -0500 Subject: status: improve parallel execution stability The status command runs a bunch of jobs in parallel, and each one is responsible for writing to stdout directly. When running many noisy jobs in parallel, output can get intermingled. Pass down a StringIO buffer for writing to so we can return the entire output as a string so the main job can handle displaying it. This fixes interleaved output as well as making the output stable: we always display results in the same project order now. By switching from map to imap, this ends up not really adding any overhead. Bug: https://crbug.com/gerrit/12231 Change-Id: Ic18b07c8074c046ff36e306eb8d392fb34fb6eca Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/297242 Tested-by: Mike Frysinger Reviewed-by: Chris Mcdonald --- command.py | 9 +++++++++ 1 file changed, 9 insertions(+) (limited to 'command.py') diff --git a/command.py b/command.py index 7737ec71..90bd0021 100644 --- a/command.py +++ b/command.py @@ -23,6 +23,15 @@ from error import NoSuchProjectError from error import InvalidProjectGroupsError +# Number of projects to submit to a single worker process at a time. +# This number represents a tradeoff between the overhead of IPC and finer +# grained opportunity for parallelism. This particular value was chosen by +# iterating through powers of two until the overall performance no longer +# improved. The performance of this batch size is not a function of the +# number of cores on the system. +WORKER_BATCH_SIZE = 32 + + # How many jobs to run in parallel by default? This assumes the jobs are # largely I/O bound and do not hit the network. DEFAULT_LOCAL_JOBS = min(os.cpu_count(), 8) -- cgit v1.2.3-54-g00ecf