sbws keeps the number of AsyncResults less than the number of threads

This ticket is a follow-up to legacy/trac#28864 (moved).

multiprocessing.Pool can accept any number of queued AsyncResults: https://docs.python.org/3/library/multiprocessing.html#multiprocessing.pool.Pool

But sbws waits for 5 seconds when there are max_pending_results queued AsyncResults: https://github.com/torproject/sbws/blob/ee64d76df54ceb3a3c9e1e2a797fd70d68bb0035/sbws/core/scanner.py#L359-L361

This sbws code is unnecessary, because Pool manages its own queue of AsyncResults.

There are two different ways that this code blocks execution:

• when a result finishes, the time.sleep(5) call blocks the thread from getting a new AsyncResult for up to 5 seconds
• if max_pending_results AsyncResults ever block, the process hangs

changed milestone to %sbws: 1.1.x-final in legacy/trac

Trac:
Parent Ticket: legacy/trac#28663 (moved)

added component::core tor/sbws in Legacy / Trac milestone::sbws: 1.1.x-final in Legacy / Trac owner::juga in Legacy / Trac parent::28663 in Legacy / Trac points::1 in Legacy / Trac priority::medium in Legacy / Trac resolution::fixed in Legacy / Trac severity::normal in Legacy / Trac status::closed in Legacy / Trac type::defect in Legacy / Trac version::sbws 1.0.2 in Legacy / Trac labels

Replying to teor: [...]

There are two different ways that this code blocks execution:

• when a result finishes, the time.sleep(5) call blocks the thread from getting a new AsyncResult for up to 5 seconds

the main thread blocks, but not the workers.

• if max_pending_results AsyncResults ever block, the process hangs

and that would mean there's a deadlock or a bug somewhere else. Probably the cause (or at least the main one) is legacy/trac#28897 (moved). What i would to detect future bugs, is give a maximum timeout to both while loops, then print a backtrace and ask the user to open a ticket with the backtrace.

Replying to juga:

What i would to detect future bugs, is give a maximum timeout to both while loops, then print a backtrace and ask the user to open a ticket with the backtrace. This was implemented in legacy/trac#28932 (moved), so this can wait to milestone 1.1. https://github.com/torproject/sbws/pull/340

Trac:
Owner: N/A to juga
Points: N/A to 1
Status: new to assigned
Milestone: sbws: 1.0.x-final to sbws: 1.1.x-final
Cc: juga, teor to N/A

Trac:
Status: assigned to needs_review

I realize this can not work with the timeout of 10 secs now.

Trac:
Status: needs_review to needs_revision

Implemented in legacy/trac#28864 (moved)

Trac:
Status: needs_revision to closed
Resolution: N/A to fixed

closed

changed time estimate to 8h

moved from legacy/trac#28865 (moved)

added Bug label and removed 1 deleted label

removed 1 deleted label