perf trace: Handle legacy syscalls tracepoints
tip-bot for Arnaldo Carvalho de Melo
merge botCommit-ID: f208bd8df08d0659ecd9e09e992c79aab26cddfa Gitweb: http://git.kernel.org/tip/f208bd8df08d0659ecd9e09e992c79aab26cddfa Author: Arnaldo Carvalho de Melo <[email protected]> AuthorDate: Fri, 20 Mar 2015 17:46:53 -0300 Committer: Arnaldo Carvalho de Melo <[email protected]> CommitDate: Sat, 21 Mar 2015 14:53:36 -0300
perf trace: Handle legacy syscalls tracepoints
Currently the code skips the first field with the expectation that it is 'nr'. But older kernels do not have the 'nr' field:
field:int nr; offset:8; size:4; signed:1;
Change perf-trace to drop the field if it exists after parsing the format file.
This fixes the off-by-one problem with older kernels (e.g., RHEL6). e.g, perf-trace shows this for write:
1.515 ( 0.006 ms): dd/4245 write(buf: 2</dev/pts/0>, count: 140733837536224 ) = 26
where 2 is really the fd, the huge number is really the buf address, etc. With this patch you get the more appropriate:
1.813 ( 0.003 ms): dd/6330 write(fd: 2</dev/pts/0>, buf: 0x7fff22fc81f0, count: 25) = 25
Based-on-a-patch-by David Ahern <[email protected]>
Acked-by David Ahern <[email protected]>
Cc Adrian Hunter <[email protected]>
Cc Borislav Petkov <[email protected]>
Cc Don Zickus <[email protected]>
Cc Frederic Weisbecker <[email protected]>
Cc Jiri Olsa <[email protected]>
Cc Namhyung Kim <[email protected]>
Cc Stephane Eranian <[email protected]>
Signed-off-by Arnaldo Carvalho de Melo <[email protected]>
--- tools/perf/builtin-trace.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)
tools/perf/builtin-trace.c +14 -4
@@ -1135,6 +1135,8 @@ static struct syscall_fmt *syscall_fmt__find(const char *name)struct syscall {struct event_format *tp_format; +int nr_args; +struct format_field *args;const char *name;bool filtered;bool is_exit;
@@ -1442,14 +1444,14 @@ static int syscall__set_arg_fmts(struct syscall *sc)struct format_field *field;int idx =0 ; - sc->arg_scnprintf =calloc (sc->tp_format->format.nr_fields -1 ,sizeof (void *)); + sc->arg_scnprintf =calloc (sc->nr_args,sizeof (void *));if (sc->arg_scnprintf ==NULL )return -1 ;if (sc->fmt) sc->arg_parm = sc->fmt->arg_parm; -for (field = sc->tp_format->format.fields->next; field; field = field->next) { +for (field = sc->args; field; field = field->next) {if (sc->fmt && sc->fmt->arg_scnprintf[idx]) sc->arg_scnprintf[idx] = sc->fmt->arg_scnprintf[idx];else if (field->flags &FIELD_IS_POINTER )
@@ -1515,6 +1517,14 @@ static int trace__read_syscall_info(struct trace *trace, int id)if (sc->tp_format ==NULL )return -1 ; + sc->args = sc->tp_format->format.fields; + sc->nr_args = sc->tp_format->format.nr_fields; +/* drop nr field - not relevant here; does not exist on older kernels */ +if (sc->args &&strcmp (sc->args->name,"nr" ) ==0 ) { + sc->args = sc->args->next; + --sc->nr_args; + } + sc->is_exit = !strcmp (name,"exit_group" ) || !strcmp (name,"exit" );return syscall__set_arg_fmts (sc);
@@ -1537,7 +1547,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size,unsigned char *p;unsigned long val; -if (sc->tp_format !=NULL ) { +if (sc->args !=NULL ) {struct format_field *field;u8 bit =1 ;struct syscall_arg arg = {
@@ -1547,7 +1557,7 @@ static size_t syscall__scnprintf_args(struct syscall *sc, char *bf, size_t size, .thread = thread, }; -for (field = sc->tp_format->format.fields->next; field; +for (field = sc->args; field; field = field->next, ++arg.idx, bit <<=1 ) {if (arg.mask & bit)continue ;