Em Mon, Dec 14, 2020 at 08:56:55PM +0800, Tiezhu Yang escreveu:
> DWARF register mappings have not been defined for some architectures,
> at least for mips, so we can print an error message and then return
> directly when use '--call-graph dwarf'.
>
> E.g. without this patch:
>
> [root@linux perf]# ./perf record --call-graph dwarf cd
> Error:
> The sys_perf_event_open() syscall returned with 89 (Function not implemented)
> for event (cycles).
> /bin/dmesg | grep -i perf may provide additional information.
>
> With this patch:
>
> [root@linux perf]# ./perf record --call-graph dwarf cd
> DWARF is not supported for architecture mips64
Good improvement on the message! But that .config-detected file isn't
available at run time, take a look if this isn't a better alternative:
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index 1b60985690bba313..125178fd17482513 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -276,6 +276,7 @@ int parse_callchain_record(const char *arg, struct
callchain_param *param)
/* Dwarf style */
} else if (!strncmp(name, "dwarf", sizeof("dwarf"))) {
+#ifdef HAVE_DWARF_SUPPORT
const unsigned long default_stack_dump_size = 8192;
ret = 0;
@@ -290,6 +291,15 @@ int parse_callchain_record(const char *arg, struct
callchain_param *param)
ret = get_stack_size(tok, &size);
param->dump_size = size;
}
+#else
+ struct utsname uts;
+
+ ret = uname(&uts);
+ pr_err("DWARF is not supported for architecture %s\n",
+ ret ? "unknown" : uts.machine);
+
+ return -ENOTSUP;
+#endif
} else if (!strncmp(name, "lbr", sizeof("lbr"))) {
if (!strtok_r(NULL, ",", &saveptr)) {
param->record_mode = CALLCHAIN_LBR;
> Usage: perf record [<options>] [<command>]
> or: perf record [<options>] -- <command> [<options>]
>
> --call-graph <record_mode[,record_size]>
> setup and enables call-graph (stack
> chain/backtrace):
>
> record_mode: call graph recording mode
> (fp|dwarf|lbr)
> record_size: if record_mode is 'dwarf', max
> size of stack recording (<bytes>)
> default: 8192 (bytes)
>
> Default: fp
>
> Signed-off-by: Tiezhu Yang <[email protected]>
> ---
> tools/perf/util/callchain.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
> index 1b60985..a8cf456 100644
> --- a/tools/perf/util/callchain.c
> +++ b/tools/perf/util/callchain.c
> @@ -18,6 +18,7 @@
> #include <math.h>
> #include <linux/string.h>
> #include <linux/zalloc.h>
> +#include <sys/utsname.h>
>
> #include "asm/bug.h"
>
> @@ -278,6 +279,16 @@ int parse_callchain_record(const char *arg, struct
> callchain_param *param)
> } else if (!strncmp(name, "dwarf", sizeof("dwarf"))) {
> const unsigned long default_stack_dump_size = 8192;
>
> + if (system("grep -q 'CONFIG_DWARF=y' .config-detected")
> != 0) {
> + struct utsname uts;
> +
> + ret = uname(&uts);
> + pr_err("DWARF is not supported for architecture
> %s\n",
> + ret ? "unknown" : uts.machine);
> +
> + return -ENOTSUP;
> + }
> +
> ret = 0;
> param->record_mode = CALLCHAIN_DWARF;
> param->dump_size = default_stack_dump_size;
> --
> 2.1.0
>
--
- Arnaldo
