[LTP] [PATCH] syscalls/setrlimit06: lower RLIMIT_CPU parameters

[Jan Stancek]

----- Original Message -----
> On Mon, Feb 10, 2020 at 8:47 PM Jan Stancek <jstancek@redhat.com> wrote:
> 
> > Lower the parameters so that test completes faster where possible.
> >
> > This also increases alarm timer slightly, which in combination with
> > lower RLIMIT_CPU aims to avoid false positives in environments with
> > high steal time, where it can take multiple of wall clock seconds
> > to spend single second on a cpu.
> >
> 
> This patch could reduce the test failure possibility, but I'm afraid it
> can't fix the problem radically, because with `stress -c 20' to overload an
> s390x system(2cpus) in the background then setrlimit06(patched) still
> easily gets failed:
>     setrlimit06.c:98: FAIL: Got only SIGXCPU after reaching both limit
> 
> Another way I can think of is to raise the priority before its running, not
> sure if that will disturb the original test but from my test, it always
> gets a pass even with too much overload.

Is this in addition to my patch? Because on its own I don't see how this
will help when load is coming from different guests.

> 
> --- a/testcases/kernel/syscalls/setrlimit/setrlimit06.c
> +++ b/testcases/kernel/syscalls/setrlimit/setrlimit06.c
> @@ -25,6 +25,7 @@
>  #include <sys/wait.h>
>  #include <stdlib.h>
>  #include <sys/mman.h>
> +#include <sys/resource.h>
> 
>  #include "tst_test.h"
> 
> @@ -37,6 +38,8 @@ static void sighandler(int sig)
> 
>  static void setup(void)
>  {
> +       setpriority(PRIO_PROCESS, 0, -20);
> +
>         SAFE_SIGNAL(SIGXCPU, sighandler);
> 
>         end = SAFE_MMAP(NULL, sizeof(int), PROT_READ | PROT_WRITE,
> @@ -110,6 +113,7 @@ static void verify_setrlimit(void)
>  }
> 
>  static struct tst_test test = {
> +       .needs_root = 1,
>         .test_all = verify_setrlimit,
>         .setup = setup,
>         .cleanup = cleanup,
> 
> --
> Regards,
> Li Wang
>