Messages in this thread | | | Date | Thu, 04 Jun 2015 14:36:04 +0530 | From | Madhavan Srinivasan <> | Subject | Re: [PATCH v1 4/9]powerpc/powernv: Add generic nest pmu ops |
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On Wednesday 03 June 2015 05:33 AM, Daniel Axtens wrote: > On Tue, 2015-06-02 at 21:29 +0530, Madhavan Srinivasan wrote: >> Patch adds generic nest pmu functions and format attribute. >> > I'm not sure this commit message accurately reflects the content of the > patch. At any rate, please could you: > - say what the patch adds the functions and attributes to. > - phrase your message as "Add generic ..." not "Patch adds > generic ...": see > https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/tree/Documentation/SubmittingPatches#n155
Sure. Will rephrase it. > >> >> +PMU_FORMAT_ATTR(event, "config:0-20"); >> +struct attribute *p8_nest_format_attrs[] = { >> + &format_attr_event.attr, >> + NULL, >> +}; >> + >> +struct attribute_group p8_nest_format_group = { >> + .name = "format", >> + .attrs = p8_nest_format_attrs, >> +}; > Can these structs be constified? I guess it can. Will check it out.
>> + >> +int p8_nest_event_init(struct perf_event *event) >> +{ >> + int chip_id; >> + >> + if (event->attr.type != event->pmu->type) >> + return -ENOENT; >> + >> + /* Sampling not supported yet */ >> + if (event->hw.sample_period) >> + return -EINVAL; >> + >> + /* unsupported modes and filters */ >> + if (event->attr.exclude_user || >> + event->attr.exclude_kernel || >> + event->attr.exclude_hv || >> + event->attr.exclude_idle || >> + event->attr.exclude_host || >> + event->attr.exclude_guest || >> + event->attr.sample_period) /* no sampling */ >> + return -EINVAL; > You test for sample period twice here. Yes right. I will remove it.
>> + >> + if (event->cpu < 0) >> + return -EINVAL; >> + >> + chip_id = topology_physical_package_id(event->cpu); >> + event->hw.event_base = event->attr.config + >> + p8_perchip_nest_info[chip_id].vbase; >> + >> + return 0; >> +} >> + >> +void p8_nest_read_counter(struct perf_event *event) >> +{ >> + u64 *addr; >> + u64 data = 0; >> + >> + addr = (u64 *)event->hw.event_base; >> + data = __be64_to_cpu((uint64_t)*addr); >> + local64_set(&event->hw.prev_count, data); >> +} >> + >> +void p8_nest_perf_event_update(struct perf_event *event) >> +{ >> + u64 counter_prev, counter_new, final_count; >> + uint64_t *addr; >> + >> + addr = (u64 *)event->hw.event_base; >> + counter_prev = local64_read(&event->hw.prev_count); >> + counter_new = __be64_to_cpu((uint64_t)*addr); >> + final_count = counter_new - counter_prev; >> + >> + local64_set(&event->hw.prev_count, counter_new); >> + local64_add(final_count, &event->count); >> +} >> + >> +void p8_nest_event_start(struct perf_event *event, int flags) >> +{ >> + event->hw.state = 0; >> + p8_nest_read_counter(event); >> +} >> + >> +void p8_nest_event_stop(struct perf_event *event, int flags) >> +{ >> + p8_nest_perf_event_update(event); >> +} >> + >> +int p8_nest_event_add(struct perf_event *event, int flags) >> +{ >> + p8_nest_event_start(event, flags); >> + return 0; >> +} >> + >> +void p8_nest_event_del(struct perf_event *event, int flags) >> +{ >> + p8_nest_event_stop(event, flags); > Is this necessary? > > Stop calls update, which I guess makes sense as it finalises the value. > But if the event is being deleted anyway, why not just do nothing here? Since these Nest PMUs does not support sampling. IIUC, "perf record" interface uses the event start/stop ops. Incase of perf stat interface event add/del interface are used to enable and disable the counters. Now, when we disable or delete, we update the event counter with the delta value.
>> +} >> + > Regards, > Daniel Axtens
Thanks for the review Maddy
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