On Tue, Apr 06, 2021 at 12:00:27PM +0100, John Garry wrote:
> On 01/04/2021 14:49, Jiri Olsa wrote:
> > On Thu, Mar 25, 2021 at 06:33:14PM +0800, John Garry wrote:
> > 
> > SNIP
> > 
> > > +struct metric {
> > > + struct list_head list;
> > > + struct metric_ref metric_ref;
> > > +};
> > > +
> > > +static int resolve_metric_simple(struct expr_parse_ctx *pctx,
> > > +                          struct list_head *compound_list,
> > > +                          struct pmu_events_map *map,
> > > +                          const char *metric_name)
> > > +{
> > > + struct hashmap_entry *cur, *cur_tmp;
> > > + struct metric *metric, *tmp;
> > > + size_t bkt;
> > > + bool all;
> > > + int rc;
> > > +
> > > + do {
> > > +         all = true;
> > > +         hashmap__for_each_entry_safe((&pctx->ids), cur, cur_tmp, bkt) {
> > > +                 struct metric_ref *ref;
> > > +                 struct pmu_event *pe;
> > > +
> > > +                 pe = metrcgroup_find_metric(cur->key, map);
> 
> *
> 
> > > +                 if (!pe)
> > > +                         continue;
> > > +
> > > +                 if (!strcmp(metric_name, (char *)cur->key)) {
> > > +                         pr_warning("Recursion detected for metric 
> > > %s\n", metric_name);
> > > +                         rc = -1;
> > > +                         goto out_err;
> > > +                 }
> > > +
> > > +                 all = false;
> > > +
> > > +                 /* The metric key itself needs to go out.. */
> > > +                 expr__del_id(pctx, cur->key);
> > > +
> > > +                 metric = malloc(sizeof(*metric));
> > > +                 if (!metric) {
> > > +                         rc = -ENOMEM;
> > > +                         goto out_err;
> > > +                 }
> > > +
> > > +                 ref = &metric->metric_ref;
> > > +                 ref->metric_name = pe->metric_name;
> > > +                 ref->metric_expr = pe->metric_expr;
> > > +                 list_add_tail(&metric->list, compound_list);
> > > +
> > > +                 rc = expr__find_other(pe->metric_expr, NULL, pctx, 0);
> > 
> 
> Hi Jirka,
> 
> > so this might add new items to pctx->ids, I think you need
> > to restart the iteration as we do it in __resolve_metric
> > otherwise you could miss some new keys
> 
> I thought that I was doing this. Indeed, this code is very much like
> __resolve_metric() ;)
> 
> So expr__find_other() may add a new item to pctx->ids, and we always iterate
> again, and try to lookup any pmu_events, *, above. If none exist, then we

hm, I don't see that.. so, what you do is:

        hashmap__for_each_entry_safe((&pctx->ids) ....) {

                rc = expr__find_other(pe->metric_expr, NULL, pctx, 0);
        }

and what I think we need to do is:

        hashmap__for_each_entry_safe((&pctx->ids) ....) {

                rc = expr__find_other(pe->metric_expr, NULL, pctx, 0);

                break;  
        }

each time you resolve another metric, you need to restart
the pctx->ids iteration, because there will be new items,
and we are in the middle of it

jirka


> have broken down pctx into primitive events aliases and unresolvable
> metrics, and stop iterating. And then unresolvable metrics would be found in
> check_parse_cpu().
> 
> As an example, we can deal with metric test1, below, which references 2x
> other metrics:
> 
>     {
>         "MetricExpr": "IDQ_UOPS_NOT_DELIVERED.CORE / (4 * (( (
> CPU_CLK_UNHALTED.THREAD / 2 ) * ( 1 + CPU_CLK_UNHALTED.ONE_THREAD_ACTIVE /
> CPU_CLK_UNHALTED.REF_XCLK ) )))",
>       "MetricName": "Frontend_Bound",
>     },
>     {
>         "MetricExpr": "( UOPS_ISSUED.ANY - UOPS_RETIRED.RETIRE_SLOTS + 4 *
> INT_MISC.RECOVERY_CYCLES ) / (4 * cycles)",
>         "MetricName": "Bad_Speculation",
>     },
>     {
>         "MetricExpr": "Bad_Speculation + Frontend_Bound",
>         "MetricName": "test1",
>     },
> 
> Does that satisfy your concern, or have I missed something?
> 
> Thanks,
> John
> 
> > 
> > jirka
> > 
> > > +                 if (rc)
> > > +                         goto out_err;
> > > +         }
> > > + } while (!all);
> > > +
> > > + return 0;
> > > +
> > > +out_err:
> > > + list_for_each_entry_safe(metric, tmp, compound_list, list)
> > > +         free(metric);
> > > +
> > > + return rc;
> > > +
> > > +}
> > 
> > SNIP
> > 
> > .
> > 
> 

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