Hi Steve:

I was hoping you could provide points on how to get access to an interpreted field in a tracepoint within perf.

This is an example of the tracepoint:

# cat /sys/kernel/debug/tracing/events/irq/softirq_exit/format
name: softirq_exit
ID: 99
format:
        field:unsigned short common_type;       offset:0;       size:2; 
signed:0;
        field:unsigned char common_flags;       offset:2;       size:1; 
signed:0;
        field:unsigned char common_preempt_count;       offset:3;       size:1; 
signed:0;
        field:int common_pid;   offset:4;       size:4; signed:1;
        field:int common_padding;       offset:8;       size:4; signed:1;

        field:unsigned int vec; offset:12;      size:4; signed:0;

print fmt: "vec=%u [action=%s]", REC->vec, __print_symbolic(REC->vec, { HI_SOFTIRQ, "HI" }, { TIMER_SOFTIRQ, "TIMER" }, { NET_TX_SOFTIRQ, "NET_TX" }, { NET_RX_SOFTIRQ, "NET_RX" }, { BLOCK_SOFTIRQ, "BLOCK" }, { BLOCK_IOPOLL_SOFTIRQ, "BLOCK_IOPOLL" }, { TASKLET_SOFTIRQ, "TASKLET" }, { SCHED_SOFTIRQ, "SCHED" }, { HRTIMER_SOFTIRQ, "HRTIMER" }, { RCU_SOFTIRQ, "RCU" })


I would like to programmatically extract the action string. 'perf script' prints the samples fine which suggests libtraceevent extracts the information somehow.

Can you provide a suggestion -- something along the lines of perf_evsel__intval() or perf_evsel__rawptr()?

Thanks,
David
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