On Mon, Feb 11, 2019 at 9:18 PM Martin Buchholz <marti...@google.com> wrote:
> Looks good to me. > > Thank you, I just pushed. > It's true that these tests depending on external tools are very brittle. > In particular, strace is in the middle of a flag re-org > > -e trace=%process > -e trace=process (deprecated) > > Nevertheless, we have such tests - are they worth the maintenance burden? > My own Zombies.java test is a good example. > It is more useful than my proposed test was. I wince a bit at the perl requirement though. Especially since the test silently quits if no perl is installed. (As a side note, I wonder whether we could have a mechanism to signal requirements not met, eg. with a TestRequirementsNotMetException, and then let the test executor decide what to do: warn, ignore, error...) I guess part of this could be redone nowadays with Rogers ProcessHandle API (the child seeking), but we still would need to find out if the child is a zombie. I like the test name btw. Very succinct :) ..Thomas > > On Mon, Feb 11, 2019 at 10:50 AM Thomas Stüfe <thomas.stu...@gmail.com> > wrote: > >> Hi Roger, Martin, >> >> hopefully final version: >> >> >> http://cr.openjdk.java.net/~stuefe/webrevs/8213192--(process)-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.03/webrev/ >> >> I removed the test and the changes in the test library made for the test. >> Test is just too brittle with too little nourishing value. Everything else >> is unchanged from webrev.02. >> >> Thank you, Thomas >> >> >> >> On Fri, Feb 8, 2019 at 10:38 AM Thomas Stüfe <thomas.stu...@gmail.com> >> wrote: >> >>> Hi Roger, Martin, >>> >>> next version: >>> >>> >>> http://cr.openjdk.java.net/~stuefe/webrevs/8213192--(process)-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.02/webrev >>> >>> - did massage the comment in ProcessImpl.c >>> - made the test more resilient by scanning for the strace tool and by >>> silently ignoring all problems stemming from strace or the payload binary >>> not being there. The test now only fails if the forks were successully >>> executed but it does not seem to use posix-spawn. >>> - added output to the test by printing the "interesting" lines of the >>> strace output. Note that this filtering is not really sophisticated and >>> will show all thread related clone() calls as well: >>> >>> 614 [pid 12447] <... clone resumed> child_stack=0x7fe00c4baff0, >>> flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, >>> parent_tidptr=0x7fe00c4bb9d0, tls=0x7fe00c4bb700, >>> child_tidptr=0x7fe00c4bb9d0) = 12452 >>> 646 [pid 12447] clone(/usr/bin/strace: Process 12453 attached >>> 649 [pid 12447] <... clone resumed> child_stack=0x7fe00c3b9ff0, >>> flags=CLONE_VM|CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|CLONE_SYSVSEM|CLONE_SETTLS|CLONE_PARENT_SETTID|CLONE_CHILD_CLEARTID, >>> parent_tidptr=0x7fe00c3ba9d0, tls=0x7fe00c3ba700, >>> child_tidptr=0x7fe00c3ba9d0) = 12453 >>> .... >>> >>> I am sure this could be made more intelligent but lets keep it simple >>> for now. >>> >>> - I removed the helperPath() methods Roger mentioned, they are not >>> needed anymore. >>> >>> @Martin: I like the -e signal=none -e trace=process idea but I'm not >>> sure if all versions of strace support these options. I think the strace >>> output is small enough for this small use case, some kB only. >>> >>> Cheers, Thomas >>> >>> >>> >>> >>> >>> On Thu, Feb 7, 2019 at 6:01 PM Thomas Stüfe <thomas.stu...@gmail.com> >>> wrote: >>> >>>> Hi all, >>>> >>>> second version, including the updated comment in ProcessImpl.c Martin >>>> requested: >>>> >>>> >>>> http://cr.openjdk.java.net/~stuefe/webrevs/8213192--(process)-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.01/webrev/index.html >>>> >>>> @Roger: thanks for feeding this into your tests. I still try to get it >>>> to run thru jdk-submit, but that seems to be stuck again.. >>>> >>>> Cheers, Thomas >>>> >>>> >>>> >>>> >>>> >>>> On Wed, Feb 6, 2019 at 10:29 AM Thomas Stüfe <thomas.stu...@gmail.com> >>>> wrote: >>>> >>>>> Hi all >>>>> >>>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8213192 >>>>> webrev: >>>>> http://cr.openjdk.java.net/~stuefe/webrevs/8213192--(process)-change-the-process-launch-mechanism-default-on-linux-to-be-posix_spawn/webrev.00/webrev/index.html >>>>> >>>>> (@Roger: I hope you do not mind? The bug is assigned to you but since >>>>> I happened to play around with posix_spawn I prepared this webrev. If you >>>>> rather do this change, that is fine and I will leave it to you.) >>>>> >>>>> When we added the possibility to use posix_spawn as underlying >>>>> implementation for Runtime.exec() on Linux with >>>>> https://bugs.openjdk.java.net/browse/JDK-8212828, we agreed to keep >>>>> VFORK as default until work on 13 starts. So now would be a good time to >>>>> switch the default to posix_spawn to get a good testing window. Note that >>>>> at SAP we run our VMs internally with posix_spawn as default since some >>>>> months and have not seen problems. >>>>> >>>>> As for the fix, I added a test which tests that the default is indeed >>>>> posix_spawn - not sure whether this is overdoing it though. Also, I use >>>>> strace for the test, and /bin/true, and while strace is usually available >>>>> and reachable by path resolution, I am afraid on some test machines it may >>>>> not. What do you think, should I leave the test out? >>>>> >>>>> The fix ran through all java/lang/ProcessBuilder jtreg tests ok. >>>>> >>>>> Thanks, Thomas >>>>> >>>>>
