Re: [PATCH] perf tool: Fix ppid for synthesized fork events
From: Don Zickus
Date: Thu Mar 19 2015 - 16:56:54 EST
On Thu, Mar 19, 2015 at 11:41:15AM -0600, David Ahern wrote:
> 363b785f38 added synthesized fork events and set a thread's parent id
> to itself. Since we are already processing /proc/<pid>/status the ppid
> can be determined properly. Make it so.
Thanks David. My tester, Joe, is currently running other tests and then is
out until Tuesday. I will try to provide test feedback by Tuesday or
Wednesday if it can wait.
Cheers,
Don
>
> Signed-off-by: David Ahern <dsahern@xxxxxxxxx>
> Cc: Don Zickus <dzickus@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> ---
> tools/perf/util/event.c | 94 ++++++++++++++++++++++++++++---------------------
> 1 file changed, 53 insertions(+), 41 deletions(-)
>
> diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
> index d5efa5092ce6..62bf7b71ac7b 100644
> --- a/tools/perf/util/event.c
> +++ b/tools/perf/util/event.c
> @@ -49,23 +49,26 @@ static struct perf_sample synth_sample = {
> .period = 1,
> };
>
> -static pid_t perf_event__get_comm_tgid(pid_t pid, char *comm, size_t len)
> +static int perf_event__get_comm_ids(pid_t pid, char *comm, size_t len,
> + pid_t *tgid, pid_t *ppid)
> {
> char filename[PATH_MAX];
> char bf[BUFSIZ];
> FILE *fp;
> size_t size = 0;
> - pid_t tgid = -1;
> +
> + *tgid = -1;
> + *ppid = -1;
>
> snprintf(filename, sizeof(filename), "/proc/%d/status", pid);
>
> fp = fopen(filename, "r");
> if (fp == NULL) {
> pr_debug("couldn't open %s\n", filename);
> - return 0;
> + return -1;
> }
>
> - while (!comm[0] || (tgid < 0)) {
> + while (!comm[0] || (*tgid < 0) || (*ppid < 0)) {
> if (fgets(bf, sizeof(bf), fp) == NULL) {
> pr_warning("couldn't get COMM and pgid, malformed %s\n",
> filename);
> @@ -86,33 +89,45 @@ static pid_t perf_event__get_comm_tgid(pid_t pid, char *comm, size_t len)
> char *tgids = bf + 5;
> while (*tgids && isspace(*tgids))
> ++tgids;
> - tgid = atoi(tgids);
> + *tgid = atoi(tgids);
> +
> + } else if (memcmp(bf, "PPid:", 5) == 0) {
> + char *ppids = bf + 5;
> +
> + while (*ppids && isspace(*ppids))
> + ++ppids;
> + *ppid = atoi(ppids);
> }
> }
>
> fclose(fp);
>
> - return tgid;
> + return 0;
> }
>
> -static pid_t perf_event__prepare_comm(union perf_event *event, pid_t pid,
> - struct machine *machine)
> +static int perf_event__prepare_comm(union perf_event *event, pid_t pid,
> + struct machine *machine,
> + pid_t *tgid, pid_t *ppid)
> {
> size_t size;
> - pid_t tgid;
> +
> + *ppid = -1;
>
> memset(&event->comm, 0, sizeof(event->comm));
>
> - if (machine__is_host(machine))
> - tgid = perf_event__get_comm_tgid(pid, event->comm.comm,
> - sizeof(event->comm.comm));
> - else
> - tgid = machine->pid;
> + if (machine__is_host(machine)) {
> + if (perf_event__get_comm_ids(pid, event->comm.comm,
> + sizeof(event->comm.comm),
> + tgid, ppid) != 0) {
> + return -1;
> + }
> + } else
> + *tgid = machine->pid;
>
> - if (tgid < 0)
> - goto out;
> + if (*tgid < 0)
> + return -1;
>
> - event->comm.pid = tgid;
> + event->comm.pid = *tgid;
> event->comm.header.type = PERF_RECORD_COMM;
>
> size = strlen(event->comm.comm) + 1;
> @@ -122,36 +137,35 @@ static pid_t perf_event__prepare_comm(union perf_event *event, pid_t pid,
> (sizeof(event->comm.comm) - size) +
> machine->id_hdr_size);
> event->comm.tid = pid;
> -out:
> - return tgid;
> +
> + return 0;
> }
>
> -static pid_t perf_event__synthesize_comm(struct perf_tool *tool,
> - union perf_event *event, pid_t pid,
> - perf_event__handler_t process,
> - struct machine *machine)
> +static int perf_event__synthesize_comm(struct perf_tool *tool,
> + union perf_event *event, pid_t pid,
> + perf_event__handler_t process,
> + struct machine *machine,
> + pid_t *tgid, pid_t *ppid)
> {
> - pid_t tgid = perf_event__prepare_comm(event, pid, machine);
> -
> - if (tgid == -1)
> - goto out;
> + if (perf_event__prepare_comm(event, pid, machine, tgid, ppid) != 0)
> + return -1;
>
> if (process(tool, event, &synth_sample, machine) != 0)
> return -1;
>
> -out:
> - return tgid;
> + return 0;
> }
>
> static int perf_event__synthesize_fork(struct perf_tool *tool,
> - union perf_event *event, pid_t pid,
> - pid_t tgid, perf_event__handler_t process,
> + union perf_event *event,
> + pid_t pid, pid_t tgid, pid_t ppid,
> + perf_event__handler_t process,
> struct machine *machine)
> {
> memset(&event->fork, 0, sizeof(event->fork) + machine->id_hdr_size);
>
> - event->fork.ppid = tgid;
> - event->fork.ptid = tgid;
> + event->fork.ppid = ppid;
> + event->fork.ptid = ppid;
> event->fork.pid = tgid;
> event->fork.tid = pid;
> event->fork.header.type = PERF_RECORD_FORK;
> @@ -343,14 +357,12 @@ static int __event__synthesize_thread(union perf_event *comm_event,
> char filename[PATH_MAX];
> DIR *tasks;
> struct dirent dirent, *next;
> - pid_t tgid;
> + pid_t tgid, ppid;
>
> /* special case: only send one comm event using passed in pid */
> if (!full) {
> - tgid = perf_event__synthesize_comm(tool, comm_event, pid,
> - process, machine);
> -
> - if (tgid == -1)
> + if (perf_event__synthesize_comm(tool, comm_event, pid,
> + process, machine, &tgid, &ppid) != 0)
> return -1;
>
> return perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid,
> @@ -378,12 +390,12 @@ static int __event__synthesize_thread(union perf_event *comm_event,
> if (*end)
> continue;
>
> - tgid = perf_event__prepare_comm(comm_event, _pid, machine);
> - if (tgid == -1)
> + if (perf_event__prepare_comm(comm_event, _pid, machine,
> + &tgid, &ppid) != 0)
> return -1;
>
> if (perf_event__synthesize_fork(tool, fork_event, _pid, tgid,
> - process, machine) < 0)
> + ppid, process, machine) < 0)
> return -1;
> /*
> * Send the prepared comm event
> --
> 2.2.1
>
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