Messages in this thread | | | Subject | Re: [PATCH v9 2/2] drivers/perf: hisi: Add driver for HiSilicon PCIe PMU | From | "liuqi (BA)" <> | Date | Wed, 25 Aug 2021 19:52:08 +0800 |
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Hi, Will On 2021/8/24 22:31, Will Deacon wrote: > Hi, > > On Wed, Aug 18, 2021 at 01:12:46PM +0800, Qi Liu wrote: >> PCIe PMU Root Complex Integrated End Point(RCiEP) device is supported >> to sample bandwidth, latency, buffer occupation etc. >> >> Each PMU RCiEP device monitors multiple Root Ports, and each RCiEP is >> registered as a PMU in /sys/bus/event_source/devices, so users can >> select target PMU, and use filter to do further sets. >> >> Filtering options contains: >> event - select the event. >> port - select target Root Ports. Information of Root Ports are >> shown under sysfs. >> bdf - select requester_id of target EP device. >> trig_len - set trigger condition for starting event statistics. >> trig_mode - set trigger mode. 0 means starting to statistic when bigger >> than trigger condition, and 1 means smaller. >> thr_len - set threshold for statistics. >> thr_mode - set threshold mode. 0 means count when bigger than threshold, >> and 1 means smaller. > > I think this is getting there now, thanks for sticking with it. Just a > couple of comments below.. > >> +static bool hisi_pcie_pmu_validate_event_group(struct perf_event *event) >> +{ >> + struct perf_event *sibling, *leader = event->group_leader; >> + int counters = 1; >> + >> + if (!is_software_event(leader)) { >> + if (leader->pmu != event->pmu) >> + return false; >> + >> + if (leader != event) >> + counters++; >> + } >> + >> + for_each_sibling_event(sibling, event->group_leader) { >> + if (is_software_event(sibling)) >> + continue; >> + >> + if (sibling->pmu != event->pmu) >> + return false; >> + >> + counters++; >> + } >> + >> + return counters <= HISI_PCIE_MAX_COUNTERS; >> +} > > Given that this function doesn't look at the event numbers, doesn't this > over-provision the counter registers? For example, if I create a group > containing 4 of the same event, then we'll allocate four counters but only > use one. Similarly, if I create a group containing two events, one for the > normal counter and one for the extended counter, then we'll again allocate > two counters instead of one. >
Yes, we should add some check in hisi_pcie_pmu_validate_event_group() function to avoid over-provision. I'll use a array to record events and do this check.
Thanks for your review, I'll fix this.
> Have I misunderstood? > >> +static int hisi_pcie_pmu_event_init(struct perf_event *event) >> +{ >> + struct hisi_pcie_pmu *pcie_pmu = to_pcie_pmu(event->pmu); >> + struct hw_perf_event *hwc = &event->hw; >> + >> + event->cpu = pcie_pmu->on_cpu; >> + >> + if (EXT_COUNTER_IS_USED(hisi_pcie_get_event(event))) >> + hwc->event_base = HISI_PCIE_EXT_CNT; >> + else >> + hwc->event_base = HISI_PCIE_CNT; >> + >> + if (event->attr.type != event->pmu->type) >> + return -ENOENT; >> + >> + /* Sampling is not supported. */ >> + if (is_sampling_event(event) || event->attach_state & PERF_ATTACH_TASK) >> + return -EOPNOTSUPP; >> + >> + if (!hisi_pcie_pmu_valid_filter(event, pcie_pmu)) { >> + pci_err(pcie_pmu->pdev, "Invalid filter!\n"); > > Please remove this message, as it's triggerable from userspace. > got it, will remove this.
Thanks, Qi > Will > . >
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