[jira] [Comment Edited] (THRIFT-4190) improve C# TThreadPoolServer defaults

["Jens Geyer (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/THRIFT-4190?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15999580#comment-15999580 ] 

Jens Geyer edited comment on THRIFT-4190 at 5/6/17 8:53 PM:
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That still does not solve the problem, that one may (for whatever reason) may want to change the numbers of threads and I/O completion ports to different values. Instead of adding two more arguments we could a) add a CTOR that expects a struct with settings, or b) simply ignore that case for now and rely on the developer to call the global thread pool methods after instantiating the Thrift server object.


was (Author: jensg):
That still does not solve the problem, that one may (for whatever reason) may want to change the numbers of threads and I/O completion ports to different values. Instead of adding two more arguments we could a) add a CTOR that expects a struct with settings, or b) ignore that case and rely on the developer to call the global thread pool methods after instantiating the Thrift server object. My favourite would be a).

> improve C# TThreadPoolServer defaults
> -------------------------------------
>
>                 Key: THRIFT-4190
>                 URL: https://issues.apache.org/jira/browse/THRIFT-4190
>             Project: Thrift
>          Issue Type: Improvement
>          Components: C# - Library
>            Reporter: Jens Geyer
>            Assignee: Jens Geyer
>
> The TThreadPoolServer uses hardcoded values to specify min/max number of threads, if the caller does not specify them. This is rather unexpected in my opinion, since the global C# ThreadPool (which is used internally) comes with its own defaults for all 4 values - yes, 4, not 2: there are different settings for the number of threads on one hand and the number of asyn IO completion ports on the other, and they are not necessary identical numbers. For example, on my machine I get these numbers by default:
> - min 4 threads and 4 I/O completion ports
> - max 37267 threads and 1000 I/O completion ports
> There are several *problems* with this approach:
> # There is really no way to bypass the defaults of min 10/10 and max 100/100 that are hard-coded into TThreadPoolServer and use the defaults provided by the NET framework instead, since we can only pass number which is then used for threads AND io ports. In my example, no matter what value I pass, 37267 or 1000, it will be something other than the defaults.
> # It is rather unexpected to have Thrift override the default settings of the global thread pool object if I don't even provide values by calling one of the simpler TThreadPoolServer  CTORs.
> # I'm not sure where the defaults are come from. Both numbers look like wild guesswork to me. The defaults provided by the runtime make much more sense, as they automatically adapt to the machine's capabilities.
> My *proposal* to solve it comes in two parts:
> # Change  the CTOR in a way that interprets 0 or negative values as intention to stick with the NET default settings. I think that is the best way to handle it, as the current implementation would just throw in a very defined way, so we don't get any compatibility conflicts here that pass undetectedly.
> # Additionally make the default values {{DEFAULT_MAX_THREADS}} and {{DEFAULT_MIN_THREADS}} both 0 (or negative) to enforce the system's defaults. Since this will be a breaking change, as it changes the current default behaviour, I'd like to know the opinions of the community before I commit that part of the changes.
> Further reference
> - [SetMinThreads method|https://msdn.microsoft.com/en-us/library/system.threading.threadpool.setminthreads(v=vs.110).aspx]
> - [SetMaxThreads method|https://msdn.microsoft.com/en-us/library/system.threading.threadpool.setmaxthreads(v=vs.110).aspx]



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