[kirkstone,2.0] bitbake-worker/runqueue: Avoid unnecessary bytes object copies

From: Etienne Cordonnier <ecordonnier@snap.com>

declaring queue=b"" creates an object of types bytes().
bytes() is an immutable object, and therefore doing "self.queue = self.queue + r"
creates a new object containing "self.queue" concatenated with "r".

On my test setup, we are passing 180MB of data of "workerdata" to the bitbake-worker,
so those copies significantly slow down the initialization of the bitbake-worker.

Rather use bytearray() which a mutable type, and use extend() to avoid copies.
In my test setup, byterray.extend() is 10.000 times faster than copying the queue,
for a queue size of 180MB.

Signed-off-by: Etienne Cordonnier <ecordonnier@snap.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
---
 bin/bitbake-worker | 14 +++++++-------
 lib/bb/runqueue.py |  4 ++--
 2 files changed, 9 insertions(+), 9 deletions(-)

Adding Steve in CC.

--
Etienne

On Fri, Sep 22, 2023 at 10:51 AM <ecordonnier@snap.com> wrote:

> From: Etienne Cordonnier <ecordonnier@snap.com>
>
> declaring queue=b"" creates an object of types bytes().
> bytes() is an immutable object, and therefore doing "self.queue =
> self.queue + r"
> creates a new object containing "self.queue" concatenated with "r".
>
> On my test setup, we are passing 180MB of data of "workerdata" to the
> bitbake-worker,
> so those copies significantly slow down the initialization of the
> bitbake-worker.
>
> Rather use bytearray() which a mutable type, and use extend() to avoid
> copies.
> In my test setup, byterray.extend() is 10.000 times faster than copying
> the queue,
> for a queue size of 180MB.
>
> Signed-off-by: Etienne Cordonnier <ecordonnier@snap.com>
> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
> ---
>  bin/bitbake-worker | 14 +++++++-------
>  lib/bb/runqueue.py |  4 ++--
>  2 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/bin/bitbake-worker b/bin/bitbake-worker
> index 5e62bc20..e02f2532 100755
> --- a/bin/bitbake-worker
> +++ b/bin/bitbake-worker
> @@ -91,19 +91,19 @@ def worker_fire_prepickled(event):
>  worker_thread_exit = False
>
>  def worker_flush(worker_queue):
> -    worker_queue_int = b""
> +    worker_queue_int = bytearray()
>      global worker_pipe, worker_thread_exit
>
>      while True:
>          try:
> -            worker_queue_int = worker_queue_int + worker_queue.get(True,
> 1)
> +            worker_queue_int.extend(worker_queue.get(True, 1))
>          except queue.Empty:
>              pass
>          while (worker_queue_int or not worker_queue.empty()):
>              try:
>                  (_, ready, _) = select.select([], [worker_pipe], [], 1)
>                  if not worker_queue.empty():
> -                    worker_queue_int = worker_queue_int +
> worker_queue.get()
> +                    worker_queue_int.extend(worker_queue.get())
>                  written = os.write(worker_pipe, worker_queue_int)
>                  worker_queue_int = worker_queue_int[written:]
>              except (IOError, OSError) as e:
> @@ -338,12 +338,12 @@ class runQueueWorkerPipe():
>          if pipeout:
>              pipeout.close()
>          bb.utils.nonblockingfd(self.input)
> -        self.queue = b""
> +        self.queue = bytearray()
>
>      def read(self):
>          start = len(self.queue)
>          try:
> -            self.queue = self.queue + (self.input.read(102400) or b"")
> +            self.queue.extend(self.input.read(102400) or b"")
>          except (OSError, IOError) as e:
>              if e.errno != errno.EAGAIN:
>                  raise
> @@ -371,7 +371,7 @@ class BitbakeWorker(object):
>      def __init__(self, din):
>          self.input = din
>          bb.utils.nonblockingfd(self.input)
> -        self.queue = b""
> +        self.queue = bytearray()
>          self.cookercfg = None
>          self.databuilder = None
>          self.data = None
> @@ -405,7 +405,7 @@ class BitbakeWorker(object):
>                      if len(r) == 0:
>                          # EOF on pipe, server must have terminated
>                          self.sigterm_exception(signal.SIGTERM, None)
> -                    self.queue = self.queue + r
> +                    self.queue.extend(r)
>                  except (OSError, IOError):
>                      pass
>              if len(self.queue):
> diff --git a/lib/bb/runqueue.py b/lib/bb/runqueue.py
> index 56952070..46ff30a7 100644
> --- a/lib/bb/runqueue.py
> +++ b/lib/bb/runqueue.py
> @@ -3101,7 +3101,7 @@ class runQueuePipe():
>          if pipeout:
>              pipeout.close()
>          bb.utils.nonblockingfd(self.input)
> -        self.queue = b""
> +        self.queue = bytearray()
>          self.d = d
>          self.rq = rq
>          self.rqexec = rqexec
> @@ -3120,7 +3120,7 @@ class runQueuePipe():
>
>          start = len(self.queue)
>          try:
> -            self.queue = self.queue + (self.input.read(102400) or b"")
> +            self.queue.extend(self.input.read(102400) or b"")
>          except (OSError, IOError) as e:
>              if e.errno != errno.EAGAIN:
>                  raise
> --
> 2.36.1.vfs.0.0
>
>