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Flush output buffers proactively #201

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Merged
nickdesaulniers merged 1 commit into from
Sep 22, 2021
Merged

Flush output buffers proactively #201

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6 changes: 6 additions & 0 deletions check_logs.py
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Original file line number Diff line number Diff line change
Expand Up @@ -132,6 +132,12 @@ def run_boot(build):
boot_qemu += ["-t", "20m"]
else:
boot_qemu += ["-t", "10m"]

# Before spawning a process with potentially different IO buffering,
# flush the existing buffers so output is ordered correctly.
sys.stdout.flush()
sys.stderr.flush()

try:
subprocess.run(boot_qemu, check=True)
except subprocess.CalledProcessError as e:
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4 changes: 3 additions & 1 deletion utils.py
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Expand Up @@ -126,10 +126,12 @@ def get_build():

def print_red(msg):
print("\033[91m%s\033[0m" % msg, file=sys.stderr)
sys.stderr.flush()

@MaskRay MaskRay Sep 18, 2021

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stderr is unbuffered and many applications leverage this property. No need for flush.

@nickdesaulniers nickdesaulniers Sep 20, 2021 •
edited
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Indeed, see also man 3 stderr:

The stream stderr is unbuffered.

TIL!

@nickdesaulniers nickdesaulniers Sep 21, 2021

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Though note that it seems that @kees is modifying the buffering of stderr for our boot wrapper script in ClangBuiltLinux/boot-utils#49.



def print_yellow(msg):
print("\033[93m%s\033[0m" % msg)
print("\033[93m%s\033[0m" % msg, file=sys.stdout)
sys.stdout.flush()


def patch_series_flag(tree):
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