Messages in this thread Patch in this message | | | Date | Mon, 14 Dec 2020 10:39:50 -0300 | From | Arnaldo Carvalho de Melo <> | Subject | Re: [PATCH] perf callchain: Return directly when use '--call-graph dwarf' under !CONFIG_DWARF |
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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 <yangtiezhu@loongson.cn> > --- > 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
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