cygrunsrv + sshd + rsync = 20 times too slow -- throttled?

Ken Brown kbrown@cornell.edu
Mon Sep 13 12:51:38 GMT 2021


On 9/13/2021 4:40 AM, Takashi Yano wrote:
> On Mon, 13 Sep 2021 08:54:31 +0900
> Takashi Yano wrote:
>> On Sun, 12 Sep 2021 17:46:47 -0400
>> Ken Brown wrote:
>>> On 9/12/2021 11:10 AM, Ken Brown wrote:
>>>> I don't see how this solves the problem.  In the case we were worried about
>>>> where we have a non-Cygwin reader, the writer has no query_hdl, and you're just
>>>> always reporting write ready, aren't you?  Or am I missing something?
>>>
>>> BTW, we could just decide that always reporting write ready in this corner case
>>> is acceptable.  But then we could just do that without going back to query_hdl.
>>
>> The various combination of cygwin and non-cygwin cases resuts in:
>>
>> W P R: current, query_hdl
>> c c c: OK     , OK
>> c c n: NG     , OK
>> c n c: OK     , OK
>> c n n: NG     , select() always report write ready
> 
> Sorry, this was not correct. In fact,
> W P R: current, query_hdl
> c c c: OK     , OK
> c c n: NG     , OK
> c n c: OK     , select() always report write ready
> c n n: NG     , select() always report write ready

What if you use query_hdl to fix the ccn case, but also keep the current code in 
raw_read that serializes the reads and avoids a large blocking read?  Would that 
avoid breaking the cnc case?

Ken


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