cpu shielding.

[Zhu Yanhai]

2012/2/6 atp <Andrew.Phillips at lmax.com>:
> Hello,
>
>  Apologies if I'm about to ask a frequently asked question - I did
> check back over the last couple of months.
>
>  Is anyone working on cpu shielding for processes inside a cpu cgroup?
>
>  We would like to run Java in containers, and unfortunately it likes to
> know how many processors there are in the system - to initialise thread
> pools and such like.
>
>  I was thinking along these lines;
>
> --- fs/proc/stat.c.orig 2010-05-21 11:32:32.941258466 +0000
> +++ fs/proc/stat.c      2010-05-21 11:40:47.681259133 +0000
> @@ -39,7 +39,9 @@
>        getboottime(&boottime);
>        jif = boottime.tv_sec;
>
> -       for_each_possible_cpu(i) {
> +//     for_each_possible_cpu(i) {
> +//     // refer to the visible cpus.
> +       for_each_cpu_and(i,cpu_possible_mask,(&current->cpus_allowed)) {
>                user = cputime64_add(user, kstat_cpu(i).cpustat.user);
>                nice = cputime64_add(nice, kstat_cpu(i).cpustat.nice);
>                system = cputime64_add(system, kstat_cpu(i).cpustat.system);
> @@ -78,7 +80,10 @@
>                (unsigned long long)cputime64_to_clock_t(steal),
>                (unsigned long long)cputime64_to_clock_t(guest),
>                (unsigned long long)cputime64_to_clock_t(guest_nice));
> -       for_each_online_cpu(i) {
> +
> +//     for_each_online_cpu(i) {
> +//     // cgroup.
> +       for_each_cpu_and(i,cpu_online_mask,(&current->cpus_allowed)) {
>
>                /* Copy values here to work around gcc-2.95.3, gcc-2.96 */
>                user = kstat_cpu(i).cpustat.user;
>
>  I'm sure that there are nicer ways of doing this, but Serge Hallyn
> suggested a while ago that I post here. Even though it says 2010, the
> patch above looks like it will go against 3.2.4 ok.
>
>  Thanks,
>     Andy
>
> --
> Andrew Phillips
> Head of Systems
>
> Direct: +44 (0)203 192 2509
> Mobile: +44 (0)7595 242 900
>
> LMAX, Yellow Building, 1A Nicholas Road,  London, W11 4AN
>
>
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Hi,
We are also facing the same problem, the current JVM Ergonomics always
assume that it self is the only JVM running on the machine, which is
obviously wrong in a multiple LXC containers/hosting box. We are using
the options like -XX:UseParallelGC -XX:ParallelGCThreads=nnn etc to by
pass its adaptive algorithm.

--
Thanks,
Zhu Yanhai