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Add note about not blocking job + minor wording fixes

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Jason Rhinelander 2 years ago
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  1. 10
      README.md

10
README.md

@ -260,7 +260,7 @@ second A arrives there are 4 threads running, but only 1 of them is an A thus th
slot for A jobs so we start the second A on a fifth thread. The third A, however, has no A jobs
available so gets queued.
Exmaple 4: BBBBBBAAA. At most 6 jobs. The 5th and 6th B's get queued (all general workers are
Example 4: BBBBBBAAA. At most 6 jobs. The 5th and 6th B's get queued (all general workers are
busy). The first and second get started (there are two unused reserved A slots), the third one gets
queued. The 5th and 6th B's are already interesting on their own: they won't be started until there
are only three active jobs; the third A won't be started until *either* there are only three active
@ -273,8 +273,7 @@ when a command with reserve threads arrived.
## Internal batch jobs
A common pattern is one where a single thread suddenly has some work that can be be parallelized.
You could (but shouldn't) employ some blocking, locking, mutex + condition variable monstrosity, but
you shouldn't.
You could employ some blocking, locking, mutex + condition variable monstrosity, but you shouldn't.
Instead LokiMQ provides a mechanism for this by allowing you to submit a batch of jobs with a
completion callback. All jobs will be queued and, when the last one finishes, the finalization
@ -350,6 +349,11 @@ in the batch job queue. This is useful when some event requires triggering some
you don't need to wait for or collect its result. (Internally this is just a convenience method
around creating a single-job, no-completion Batch job).
You generally do *not* want to use single (or batched) jobs for operations that can block
indefinitely (such as network operations) because each such job waiting on some external condition
ties up a thread. You are better off in such a case using your own asynchronous operations and
either using your own thread or a periodic timer (see below) to shepherd those operations.
## Timers
LokiMQ supports scheduling periodic tasks via the `add_timer()` function. These timers have an

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