Hi Yonghong, With TraceCompass XML analyses, you can use as state value or attribute an eventField called 'cpu' to get the CPU id of an event. For example,
<stateAttribute type="eventField" value="cpu" /> With LTTng traces, it will automatically be the CPU, obtained as Mathieu described, no need for an extra field. Regards, Geneviève On 2019-01-21 4:21 p.m., Yonghong Yan wrote: > Thank you. make sense. I am using Trace Compass XML based approach to > display UST trace records. Using CPU id helps me easier to sort out > the event records in trace compass. I will check out more on trace > compass. > > Yonghong > > > On Mon, Jan 21, 2019 at 2:06 PM Mathieu Desnoyers > <mathieu.desnoy...@efficios.com > <mailto:mathieu.desnoy...@efficios.com>> wrote: > > > ----- On Jan 21, 2019, at 12:14 PM, Yonghong Yan > <yany...@gmail.com <mailto:yany...@gmail.com>> wrote: > > I saw there is cpu_id field in babeltrace list, how can I add > it to the context of UST tracepoint events. lttng add-context > --list does not show that field and I do not see a similar > field for the cpu_id. > > > The cpu_id context only exists for the purpose of lttng-ust and > lttng-modules filtering. > (e.g. lttng enable-event {-u,-k} --filter '$ctx.cpu_id == 2'). > > It is not possible to add it as context to the streams, because > its information would > be completely redundant with the fact that all the data is written > into per-cpu buffers, > and the cpu_id field is available within each packet context > (which is right after each > packet header). > > You just need to use babeltrace to convert to text, and while > doing so, it prints a > "cpu_id = N" context based on the packet_context cpu_id field for > each event. > > Thanks, > > Mathieu > > -- > Mathieu Desnoyers > EfficiOS Inc. > http://www.efficios.com > > > _______________________________________________ > lttng-dev mailing list > lttng-dev@lists.lttng.org > https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev
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