V15 and ⎕WA for WS "Garbage Cleanup"

General APL language issues

V15 and ⎕WA for WS "Garbage Cleanup"

Postby woody on Tue Apr 11, 2017 3:31 pm


2 questions specific about the current Dyalog V15 (64bit)

1. If I set the maxws to 1000M (1 GB) ... How much real memory will APL Allocate when it starts up? (is there a formula ? like WS-SIZE + 5% of total allocated memory?

2. I see the Server task manager reporting growing memory usage for an APL instance (to be expected). I also see that executing ⎕WA will REDUCE the amount of Memory used by the server for APL. Why is this? Is there any advantage for cleaning up the garbage in the workspace? Or will APL take care of it when it reaches MAX Allocation ?


Woodley Butler
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Re: V15 and ⎕WA for WS "Garbage Cleanup"

Postby Richard|Dyalog on Tue Apr 11, 2017 10:24 pm

You have deduced what is happening almost exactly. There's an explanation of it here:

http://help.dyalog.com/15.0/Content/Use ... gement.htm

Explicitly using ⎕WA to return memory to the operating system is worthwhile in applications that occasionally require large amounts of workspace, so that they do not continue to hold the memory allocation after it is needed. However, ⎕WA is an expensive operation and it would not make sense to do this indiscriminately. Some memory manager statistics are available using 2000⌶, which may help the application decide whether using ⎕WA is worthwhile - this I-Beam is documented here:

http://help.dyalog.com/15.0/Content/Lan ... istics.htm
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Re: V15 and ⎕WA for WS "Garbage Cleanup"

Postby AndyS|Dyalog on Wed Apr 12, 2017 8:18 am

In addition to the pages in the documentation that Richard mentions, I spent some time talking about some of the inner workings of workspaces in Uncle Andy's Fireside chat V2 (and a little in V3). It might be worth at least skimming through the slides, links to which can be found on the User Meeting webpages at
https://www.dyalog.com/user-meetings/dyalog15.htm and https://www.dyalog.com/user-meetings/dyalog16.htm, and if you want help sleeping, you can take a look at the videos too !
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