RFR: 8233712: Limit default tests jobs based on ulimit -u setting

[Erik Joelsson]

Hello Severin,

Taking ulimit -u into account does seem like a good idea. I don't see 
why it needs to be limited to just aarch64 though. It should however be 
limited to OSes that use ulimit (i.e. not windows).

I would suggest removing the arbitrary thresholds of 16 and 4096 and try 
to come up with a plain number based on the ulimit value. You are saying 
14 is good for 4096, so the formula for the ULIMIT_DIVIDER is 4096 / 14, 
which you can just write as:

ULIMIT_DIVIER := (4096 / 14)

And let the awk script calculate it if needed. In the awk script, you 
need to put line 275 as conditional of the if statement on line 274. 
Otherwise ULIMIT=-1 will cause concurrency -1.

/Erik

On 2019-11-07 06:59, Severin Gehwolf wrote:
> Hi,
>
> Could I please get a review of this change for running tests on big
> Aarch64 boxes? Currently, only memory and number of cores are taken
> into account for the -concurrency setting of jtreg. After this patch
> ulimit -u settings are taken into account as well on big Aarch64 boxes
> with > 16 cores, yet low ulimit -u setting (<= 4096). This is to avoid
> running into the max allowed threads limit causing random test
> failures.
>
> Thoughts?
>
> Bug: https://bugs.openjdk.java.net/browse/JDK-8233712
> webrev: http://cr.openjdk.java.net/~sgehwolf/webrevs/JDK-8233712/01/webrev/
>
> Testing: Ran tier1 tests on a large Aarch64 box and low ulimit -u
> value. Tests run stable. Did the same for a user with high ulimit -u
> value, which resulted in concurrency setting as before this patch.
>
> Thanks,
> Severin
>