[Async-sig] "read-write" synchronization

[Chris Jerdonek]

The read-write operations I'm protecting will have coroutines inside
that need to be awaited on, so I don't think I'll be able to take
advantage to that extreme.

But I think I might be able to use your point to simplify the logic a
little. (To rephrase, you're reminding me that context switches can't
happen at arbitrary lines of code. I only need to be prepared for the
cases where there's an await / yield from.)

--Chris


On Sun, Jun 25, 2017 at 2:30 PM, Guido van Rossum <gvanrossum at gmail.com> wrote:
> The secret is that as long as you don't yield no other task will run so you
> don't need locks at all.
>
> On Jun 25, 2017 2:24 PM, "Chris Jerdonek" <chris.jerdonek at gmail.com> wrote:
>>
>> Thank you. I had seen that, but it seems heavier weight than needed.
>> And it also requires locking on reading.
>>
>> --Chris
>>
>> On Sun, Jun 25, 2017 at 2:16 PM, Andrew Svetlov
>> <andrew.svetlov at gmail.com> wrote:
>> > There is https://github.com/aio-libs/aiorwlock
>> >
>> > On Mon, Jun 26, 2017 at 12:13 AM Chris Jerdonek
>> > <chris.jerdonek at gmail.com>
>> > wrote:
>> >>
>> >> I'm relatively new to async programming in Python and am thinking
>> >> through possibilities for doing "read-write" synchronization.
>> >>
>> >> I'm using asyncio, and the synchronization primitives that asyncio
>> >> exposes are relatively simple [1]. Have options for async read-write
>> >> synchronization already been discussed in any detail?
>> >>
>> >> I'm interested in designs where "readers" don't need to acquire a lock
>> >> -- only writers. It seems like one way to deal with the main race
>> >> condition I see that comes up would be to use loop.time(). Does that
>> >> ring a bell, or might there be a much simpler way?
>> >>
>> >> Thanks,
>> >> --Chris
>> >>
>> >>
>> >> [1] https://docs.python.org/3/library/asyncio-sync.html
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>> > --
>> > Thanks,
>> > Andrew Svetlov
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