Messages in this thread | | | Date | Tue, 26 Jan 2021 16:55:00 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH 01/12] perf/core: Add PERF_SAMPLE_WEIGHT_EXT |
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On Tue, Jan 26, 2021 at 10:33:18AM -0500, Liang, Kan wrote: > > > On 1/26/2021 9:42 AM, Peter Zijlstra wrote: > > On Tue, Jan 19, 2021 at 12:38:20PM -0800, kan.liang@linux.intel.com wrote: > > > > > @@ -900,6 +901,13 @@ enum perf_event_type { > > > * char data[size]; } && PERF_SAMPLE_AUX > > > * { u64 data_page_size;} && PERF_SAMPLE_DATA_PAGE_SIZE > > > * { u64 code_page_size;} && PERF_SAMPLE_CODE_PAGE_SIZE > > > + * { union { > > > + * u64 weight_ext; > > > + * struct { > > > + * u64 instr_latency:16, > > > + * reserved:48; > > > + * }; > > > + * } && PERF_SAMPLE_WEIGHT_EXT > > > * }; > > > */ > > > PERF_RECORD_SAMPLE = 9, > > > @@ -1248,4 +1256,12 @@ struct perf_branch_entry { > > > reserved:40; > > > }; > > > +union perf_weight_ext { > > > + __u64 val; > > > + struct { > > > + __u64 instr_latency:16, > > > + reserved:48; > > > + }; > > > +}; > > > + > > > #endif /* _UAPI_LINUX_PERF_EVENT_H */ > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > > index 55d1879..9363d12 100644 > > > --- a/kernel/events/core.c > > > +++ b/kernel/events/core.c > > > @@ -1903,6 +1903,9 @@ static void __perf_event_header_size(struct perf_event *event, u64 sample_type) > > > if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE) > > > size += sizeof(data->code_page_size); > > > + if (sample_type & PERF_SAMPLE_WEIGHT_EXT) > > > + size += sizeof(data->weight_ext); > > > + > > > event->header_size = size; > > > } > > > @@ -6952,6 +6955,9 @@ void perf_output_sample(struct perf_output_handle *handle, > > > perf_aux_sample_output(event, handle, data); > > > } > > > + if (sample_type & PERF_SAMPLE_WEIGHT_EXT) > > > + perf_output_put(handle, data->weight_ext); > > > + > > > if (!event->attr.watermark) { > > > int wakeup_events = event->attr.wakeup_events; > > > > This patch is broken and will expose uninitialized kernel stack. > > > > Could we initialize the 'weight_ext' in perf_sample_data_init()?
No. Also see my other mail for why I hate this thing.
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