Messages in this thread | | | Subject | Re: [PATCH v7 2/2] drivers/perf: hisi: Add driver for HiSilicon PCIe PMU | From | "liuqi (BA)" <> | Date | Mon, 28 Jun 2021 18:49:57 +0800 |
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On 2021/6/26 19:44, John Garry wrote: > On 26/06/2021 03:13, liuqi (BA) wrote: >> >> >> On 2021/6/25 23:53, John Garry wrote: >>> On 24/06/2021 11:59, Qi Liu wrote: >>>> + >>>> +/* >>>> + * Events with the "dl" suffix in their names count performance in >>>> DL layer, >>>> + * otherswise, events count performance in TL layer. >>>> + */ >>>> +static struct attribute *hisi_pcie_pmu_events_attr[] = { >>>> + HISI_PCIE_PMU_EVENT_ATTR(bw_rx_mwr, 0x010004), >>>> + HISI_PCIE_PMU_EVENT_ATTR(bw_rx_mrd, 0x100005), >>>> + HISI_PCIE_PMU_EVENT_ATTR(bw_tx_mwr, 0x010005), >>>> + HISI_PCIE_PMU_EVENT_ATTR(bw_tx_mrd, 0x200004), >>>> + HISI_PCIE_PMU_EVENT_ATTR(lat_rx_mwr, 0x000010), >>>> + HISI_PCIE_PMU_EVENT_ATTR(lat_rx_mrd, 0x020010), >>>> + HISI_PCIE_PMU_EVENT_ATTR(lat_tx_mrd, 0x000011), >>>> + HISI_PCIE_PMU_EVENT_ATTR(bw_rx_dl, 0x010084), >>>> + HISI_PCIE_PMU_EVENT_ATTR(bw_tx_dl, 0x030084), >>>> + NULL >>>> +}; >>>> + >>>> +static struct attribute_group hisi_pcie_pmu_events_group = { >>>> + .name = "events", >>>> + .attrs = hisi_pcie_pmu_events_attr, >>>> +}; >>>> + >>>> +static struct attribute *hisi_pcie_pmu_format_attr[] = { >>>> + HISI_PCIE_PMU_FORMAT_ATTR(event, "config:0-15"), >>>> + HISI_PCIE_PMU_FORMAT_ATTR(subevent, "config:16-23"), >>>> + HISI_PCIE_PMU_FORMAT_ATTR(thr_len, "config1:0-3"), >>>> + HISI_PCIE_PMU_FORMAT_ATTR(thr_mode, "config1:4"), >>>> + HISI_PCIE_PMU_FORMAT_ATTR(trig_len, "config1:5-8"), >>>> + HISI_PCIE_PMU_FORMAT_ATTR(trig_mode, "config1:9"), >>>> + HISI_PCIE_PMU_FORMAT_ATTR(port, "config2:0-15"), >>>> + HISI_PCIE_PMU_FORMAT_ATTR(bdf, "config2:16-31"), >>>> + NULL >>>> +}; >>> >>> I am just wondering how this now works. >>> >>> So if the user programs the following: >>> ./perf stat -v -e hisi_pcieX/lat_rx_mrd/ >>> >>> Then the value (incremented) in HISI_PCIE_CNT (I think that's the >>> right one) is returned as the event count. But one would expect >>> bandwidth from that event, while we only return here the delay cycles >>> - how is the count in HISI_PCIE_CNT_EXT exposed, so userspace can do >>> the calc for bw? >>> >> > > Hi Qi, > >> >> Hardware counter and ext_counter work together for bandwidth, latency, >> bus utilization and buffer occupancy events. For example, for latency >> events(idx = 0x10), counter counts total delay cycles and ext_counter >> counts PCIe packets number. >> >> As we don't want PMU driver to process these two data, "delay cycles" >> can be treated as an event(id = 0x10), "packets number" as another event >> (id = 0x10 << 8), and driver could export these data separately. >> >> if the user want to calculate latency of rx memory read, they should: >> ./perf stat -v -e '{hisi_pcieX/event=0x10, >> subevent=0x01/,hisi_pcieX/event=0x0400, subevent=0x01/ >> >> and for bandwidth event: >> ./perf stat -v -e '{hisi_pcieX/event=0x4, >> subevent=0x02/,hisi_pcieX/event=0x1000, subevent=0x02/ > Hi John, > I would suggest supporting a perf metric for this then, which would be > like: > > { > "BriefDescription": "Latency for inbound traffic...", > "MetricName": "hisi_pcie_lat_rx_mrd", > "MetricExpr": "hisi_pcieX@event\\=0x4@subevent\\=0x02 \ > hisi_pcieX@event\\=0x1000@subevent\\=0x02 \", > "Unit": "hisi_pci", > "Compat": "v1" > }, > > (syntax may be incorrect - illustration only) > yes, we could add these metrics in json file, thanks. >> >> Then the value in HISI_PCIE_CNT and HISI_PCIE_EXT_CNT returned >> separately, and userspace could do the calculation. > > But I am still curious about lat_rx_mrd and the other events which we > continue to advertise. They don't really provide latency or bandwidth on > their own, but only half the necessary data. So I doubt their purpose. > So how about changing the event name to show the real purpose of this event, like changing "bw_rx_mrd" to "flux_rx_mrd", and changing "lat_rx_mrd" to "delay_rx_mrd"?
Thanks, Qi
> Thanks, > John > > .
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