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27ddc1d7a6
Add a new callchain record mode option for deferred callchains. For now
it only works with FP (frame-pointer) mode.
And add the missing feature detection logic to clear the flag on old
kernels.
$ perf record --call-graph fp,defer -vv true
...
------------------------------------------------------------
perf_event_attr:
type 0 (PERF_TYPE_HARDWARE)
size 136
config 0 (PERF_COUNT_HW_CPU_CYCLES)
{ sample_period, sample_freq } 4000
sample_type IP|TID|TIME|CALLCHAIN|PERIOD
read_format ID|LOST
disabled 1
inherit 1
mmap 1
comm 1
freq 1
enable_on_exec 1
task 1
sample_id_all 1
mmap2 1
comm_exec 1
ksymbol 1
bpf_event 1
defer_callchain 1
defer_output 1
------------------------------------------------------------
sys_perf_event_open: pid 162755 cpu 0 group_fd -1 flags 0x8
sys_perf_event_open failed, error -22
switching off deferred callchain support
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>