Bug 12054
| Summary: | exclusive cpusets are not causing unique root-domains | ||
|---|---|---|---|
| Product: | Other | Reporter: | Greg Haskins (gregory.haskins) |
| Component: | Other | Assignee: | Greg Haskins (gregory.haskins) |
| Status: | CLOSED PATCH_ALREADY_AVAILABLE | ||
| Severity: | normal | CC: | a.p.zijlstra, mingo, sivanich |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 2.6.28-rc1 | Subsystem: | |
| Regression: | --- | Bisected commit-id: | |
This issue has been fixed in upstream via commit f29c9b1ccb52904ee442a933cf3dee628f9f4e62 Dimitri, please reopen if you find that the issue still exists. |
On Mon, 2008-11-03 at 15:07 -0600, Dimitri Sivanich wrote: > > >> When load balancing gets switched off for a set of cpus via the > >> sched_load_balance flag in cpusets, those cpus wind up with the > >> globally defined def_root_domain attached. The def_root_domain is > >> attached when partition_sched_domains calls detach_destroy_domains(). > >> A new root_domain is never allocated or attached as a sched domain > >> will never be attached by __build_sched_domains() for the non-load > >> balanced processors. > >> > >> The problem with this scenario is that on systems with a large number > >> of processors with load balancing switched off, we start to see the > >> cpupri->pri_to_cpu->lock in the def_root_domain becoming contended. > >> This starts to become much more apparent above 8 waking RT threads > >> (with each RT thread running on it's own cpu, blocking and waking up > >> continuously). > >>