On Tue, Jun 24, 2014 at 05:00:52PM -0700, Sukadev Bhattiprolu wrote:
> [PATCH v5 1/1] powerpc/perf: Adjust callchain based on DWARF debug info
superflous ^^^
>
> When saving the callchain on Power, the kernel conservatively saves excess
> entries in the callchain. A few of these entries are needed in some cases
> but not others. We should use the DWARF debug information to determine
> when the entries are needed.
SNIP
> diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
> index 0e5fea9..6221d01 100644
> --- a/tools/perf/util/machine.c
> +++ b/tools/perf/util/machine.c
> @@ -1291,7 +1291,9 @@ static int machine__resolve_callchain_sample(struct
> machine *machine,
> u8 cpumode = PERF_RECORD_MISC_USER;
> int chain_nr = min(max_stack, (int)chain->nr);
> int i;
> + int j;
> int err;
> + int skip_idx;
>
> callchain_cursor_reset(&callchain_cursor);
>
> @@ -1300,14 +1302,26 @@ static int machine__resolve_callchain_sample(struct
> machine *machine,
> return 0;
> }
>
> + /*
> + * Based on DWARF debug information, some architectures skip
> + * a callchain entry saved by the kernel.
> + */
> + skip_idx = arch_skip_callchain_idx(machine, thread, chain);
> +
> for (i = 0; i < chain_nr; i++) {
> u64 ip;
> struct addr_location al;
>
> if (callchain_param.order == ORDER_CALLEE)
> - ip = chain->ips[i];
> + j = i;
> else
> - ip = chain->ips[chain->nr - i - 1];
> + j = chain->nr - i - 1;
> +
> +#ifdef HAVE_SKIP_CALLCHAIN_IDX
> + if (j == skip_idx)
> + continue;
> +#endif
> + ip = chain->ips[j];
>
> if (ip >= PERF_CONTEXT_MAX) {
> switch (ip) {
> --
> 1.7.9.5
>
got following compile error:
CC util/map.o
util/machine.c: In function ‘machine__resolve_callchain_sample’:
util/machine.c:1286:6: error: variable ‘skip_idx’ set but not used
[-Werror=unused-but-set-variable]
int skip_idx;
^
cc1: all warnings being treated as errors
make[2]: *** [util/machine.o] Error 1
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [all] Error 2
test: test -x ./perf
make: *** [make_pure] Error 1
you could use __maybe_unused for the 'skip_idx'
jirka
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