cpu shielding.
Serge Hallyn
serge.hallyn at canonical.com
Tue Feb 7 02:15:27 UTC 2012
Quoting 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,(¤t->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,(¤t->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
I'm afraid I haven't been following recent upstream discussions on
this, but there are other people who want proc to show cgroup-limited
information. See for instance http://lwn.net/Articles/460310/ . Glauber
has also brought this up since then. I'd recommend pinging him.
I'm all for /proc showing cgroup-filtered information, unconditionally.
-serge
More information about the Containers
mailing list