On Wed, 1 Mar 2017, Thomas Gleixner wrote:
WARN_ON(c->x86_cache_occ_scale != cqm_l3_scale);
@@ -1585,12 +1580,17 @@ static int intel_cqm_cpu_starting(unsigned int cpu)
static int intel_cqm_cpu_exit(unsigned int cpu)
{
+ struct intel_pqr_state *state = &per_cpu(pqr_state, cpu);
Can be this_cpu_ptr() because the callback is guaranteed to run on the
outgoing CPU.
Will fix this. Assumed the calls are setup cache alloc way -
cpuhp_setup_state(CPUHP_AP_ONLINE_DYN ..
int target;
/* Is @cpu the current cqm reader for this package ? */
if (!cpumask_test_and_clear_cpu(cpu, &cqm_cpumask))
return 0;
So if the CPU is not the current cqm reader then the per cpu state of this
CPU is left stale. Great improvement.
+ state->rmid = 0;
+ state->rmid_usecnt = 0;
+ wrmsr(MSR_IA32_PQR_ASSOC, 0, state->closid);
What clears state->closid? And what guarantees that state->rmid is not
updated before the CPU has really gone away?
- The rdt code takes care of clearing closid state now. Will update the comment.
- The cqm however was never writing a zero to PQR_ASSOC.
So the update needs to be - to remove the state->closid = 0 from cqm code as the
rdt code takes care of closid state in clear_closid() called from both offline and
online cpu.
And also write a rmid = 0 to PQR_ASSOC.
We can integrate the two of these hot cpu calls(from cat and cqm) to write PQR
only once.
guess I can skip all of these and send it as part of cqm changes we planned
anyways, because this is really a cqm change.
Thanks,
Vikas
