Another group is working on system policy. They are thinking
of settings such as max-power-savings, max-performance,
elastic, etc. One way to implement these system policies may
be to ignore different processor groups similar to this.
Do we want policy to be at the thread level or at the system
level?
Regards,
Bill
On 10/20/08 23:43, Li, Aubrey wrote:
> Eric.Saxe wrote:
>
>
>> Because it works top down, in this case, the coalescence policy will
>> be implemented until there's nothing more to do at that level, before
>> moving lower. This is the first time we've allowed different
>> policies to
>> be implemented across the hierarchy, so i'm really happy you are
>> taking a look at this. I haven't looked at it closely yet since I've
>> still been
>> focused on getting the nuts and bolts of the dispatcher driven
>> p-state changes to happen... :)
>>
>
> Currently we have two kinds of cmt policy across the hierarchical processor
> group. So it's possible a thread want to be dispatched by the performance
> policy but there is only power related processor group avaiable.
>
> The following patch adds a member into kthread_t structure, and use the same
> event driver which is used to notify cpupm to change p-state, to make the next
> kernel thread sensitive to the cmt policy, so that in later cmt balance, we
> can choose cpu by searching the related target processor group, unrelated
> groups will be ignored.
>
> What do you think?
>
> Thanks,
> -Aubrey
>
> diff -r 7bc9bb1331de usr/src/uts/common/disp/cmt.c
> --- a/usr/src/uts/common/disp/cmt.c Tue Oct 21 10:17:20 2008 +0800
> +++ b/usr/src/uts/common/disp/cmt.c Tue Oct 21 14:24:01 2008 +0800
> @@ -951,6 +951,7 @@
> {
> pg_cmt_t *cmt = (pg_cmt_t *)pg;
> cpupm_domain_t *dom;
> + pghw_type_t pghw_hw = ((pghw_t *)pg)->pghw_hw;
> uint32_t u;
>
> if (old == cp->cpu_idle_thread) {
> @@ -960,7 +961,6 @@
> * significant increase in utiliation unless the thread makes
> * it through one time slice expiration.
> */
> - ASSERT((cp->cpu_disp_flags & CPU_DISP_CMT_TRANS) == 0);
> cp->cpu_disp_flags |= CPU_DISP_CMT_TRANS;
>
> } else if (new == cp->cpu_idle_thread) {
> @@ -984,8 +984,16 @@
> * zero, so we should notify the CPUPM subsystem.
> */
> if (u == 1) {
> - dom = (cpupm_domain_t
> *)cmt->cmt_pg.pghw_handle;
> - cpupm_utilization_change(cp, dom, 0);
> + if (pghw_hw == PGHW_POW_ACTIVE) {
> + dom = (cpupm_domain_t *)
> + cmt->cmt_pg.pghw_handle;
> + cpupm_utilization_change(cp, dom, 0);
> + }
> + /*
> + * next thread will be dispatched by power
> + * policy
> + */
> + new->t_cmt_policy = CMT_COALESCE;
> }
> }
> } else {
> @@ -1004,6 +1012,7 @@
> {
> pg_cmt_t *cmt = (pg_cmt_t *)pg;
> cpupm_domain_t *dom;
> + pghw_type_t pghw_hw = ((pghw_t *)pg)->pghw_hw;
> uint32_t u;
>
> /*
> @@ -1029,8 +1038,15 @@
> * the CPUPM subsystem.
> */
> if (u == 0) {
> - dom = (cpupm_domain_t *)cmt->cmt_pg.pghw_handle;
> - cpupm_utilization_change(cp, dom, 1);
> + if (pghw_hw == PGHW_POW_ACTIVE) {
> + dom = (cpupm_domain_t
> *)cmt->cmt_pg.pghw_handle;
> + cpupm_utilization_change(cp, dom, 1);
> + }
> + /*
> + * next thread will be dispatched by the performance
> + * policy
> + */
> + t->t_cmt_policy = CMT_BALANCE;
> }
> }
> }
> diff -r 7bc9bb1331de usr/src/uts/common/disp/cmt_policy.c
> --- a/usr/src/uts/common/disp/cmt_policy.c Tue Oct 21 10:17:20 2008 +0800
> +++ b/usr/src/uts/common/disp/cmt_policy.c Tue Oct 21 14:24:01 2008 +0800
> @@ -140,6 +140,26 @@
> do {
> pg = GROUP_ACCESS(cmt_pgs, level);
>
> + /*
> + * if next thread is dispatched by the performance
> + * policy, power related group should be ignored
> + */
> + if (tp->t_cmt_policy == CMT_BALANCE) {
> + if (pg->cmt_policy & CMT_COALESCE) {
> + continue;
> + }
> + /*
> + * if next thread is dispatched by the power
> + * policy, loading balance related group should
> + * be ignored
> + */
> +
> + } else if (tp->t_cmt_policy == CMT_COALESCE) {
> + if (pg->cmt_policy & CMT_BALANCE) {
> + continue;
> + }
> + }
> +
> siblings = pg->cmt_siblings;
> nsiblings = GROUP_SIZE(siblings); /* self inclusive */
> if (nsiblings == 1)
> diff -r 7bc9bb1331de usr/src/uts/common/sys/thread.h
> --- a/usr/src/uts/common/sys/thread.h Tue Oct 21 10:17:20 2008 +0800
> +++ b/usr/src/uts/common/sys/thread.h Tue Oct 21 14:24:01 2008 +0800
> @@ -342,6 +342,7 @@
> hrtime_t t_hrtime; /* high-res last time on cpu */
> kmutex_t t_ctx_lock; /* protects t_ctx in removectx() */
> struct waitq *t_waitq; /* wait queue */
> + uint_t t_cmt_policy; /* cmt policy */
> } kthread_t;
>
> /*
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