Messages in this thread | | | Subject | Re: [PATCH] perf callchain: Return directly when use '--call-graph dwarf' under !CONFIG_DWARF | From | Tiezhu Yang <> | Date | Tue, 15 Dec 2020 09:25:42 +0800 |
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On 12/14/2020 09:39 PM, Arnaldo Carvalho de Melo wrote: > 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:
Hi Arnaldo,
Thank you very much, the following code with #ifdef HAVE_DWARF_SUPPORT looks good and it works well on the x86 and mips arch.
So I will send a v2 patch as soon as possible.
Thanks, Tiezhu
> > 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 >>
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