On Tue, 3 Dec 2019 12:35:17 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:
> New trace.dat option is introduced: TRACECMD_OPTION_GUEST.
> Written in the host's trace.dat file, it contains information about
> guests, traced at the same time: guest trace ID, number of VCPUs and
> PIDs of the host tasks, running those VCPU. The data is stored in
> the file as NULL terminated string:
> "Guest %s %llu %d\n" -> guest name, number of VCPUs
> "%d %d\n" -> VCPU, PID of host task
> .....
> "%d %d\n" -> VCPU, PID of host task
>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
> ---
> include/trace-cmd/trace-cmd.h | 1 +
> lib/trace-cmd/trace-input.c | 113 ++++++++++++++++++++++++++++++++++
> tracecmd/trace-record.c | 45 ++++++++++++++
> 3 files changed, 159 insertions(+)
>
> diff --git a/include/trace-cmd/trace-cmd.h b/include/trace-cmd/trace-cmd.h
> index 1240b4a..17badf2 100644
> --- a/include/trace-cmd/trace-cmd.h
> +++ b/include/trace-cmd/trace-cmd.h
> @@ -88,6 +88,7 @@ enum {
> TRACECMD_OPTION_PROCMAPS,
> TRACECMD_OPTION_TRACEID,
> TRACECMD_OPTION_TIME_SHIFT,
> + TRACECMD_OPTION_GUEST,
> };
>
> enum {
> diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
> index a6b675a..e36ebaa 100644
> --- a/lib/trace-cmd/trace-input.c
> +++ b/lib/trace-cmd/trace-input.c
> @@ -79,6 +79,14 @@ struct ts_offset_sample {
> long long offset;
> };
>
> +struct guest_trace_info {
> + struct guest_trace_info *next;
> + char *name;
> + unsigned long long trace_id;
> + int vcpu_count;
> + int *cpu_pid;
> +};
> +
> struct host_trace_info {
> bool sync_enable;
> unsigned long long trace_id;
> @@ -112,6 +120,7 @@ struct tracecmd_input {
> char * trace_clock;
> struct input_buffer_instance *buffers;
> int parsing_failures;
> + struct guest_trace_info *guest;
>
> struct tracecmd_ftrace finfo;
>
> @@ -2294,6 +2303,73 @@ static int trace_traceid_load(struct tracecmd_input *handle, char *buf)
> return -1;
> }
>
> +static void trace_guests_free(struct tracecmd_input *handle)
> +{
> + struct guest_trace_info *guest;
> +
> + while (handle->guest) {
> + guest = handle->guest;
> + handle->guest = handle->guest->next;
> + free(guest->name);
> + free(guest->cpu_pid);
> + free(guest);
> + }
> +}
> +
> +static int trace_guest_load(struct tracecmd_input *handle, char *buf)
> +{
> + struct guest_trace_info *guest = NULL;
> + unsigned long long tid;
> + char *line;
> + int cpu, pid;
> +
> + line = strchr(buf, '\n');
> + if (!line)
> + goto error;
> + *line = '\0';
> +
> + guest = calloc(1, sizeof(struct guest_trace_info));
> + if (!guest)
> + goto error;
> +
> + if (sscanf(buf, "%*s %ms %llu %d", &guest->name, &tid, &cpu) != 3)
> + goto error;
> + guest->trace_id = tid;
> + guest->vcpu_count = cpu;
> +
> + guest->cpu_pid = calloc(guest->vcpu_count, sizeof(int));
> + if (!guest->cpu_pid)
> + goto error;
> +
> + buf = line + 1;
> + line = strchr(buf, '\n');
> + while (line) {
> + *line = '\0';
> + if (sscanf(buf, "%d %d", &cpu, &pid) != 2)
> + goto error;
> +
> + if (cpu < guest->vcpu_count)
> + guest->cpu_pid[cpu] = pid;
> + buf = line + 1;
> + if (!*buf)
> + break;
> +
> + line = strchr(buf, '\n');
Hmm, strtok_r() seems more appropriate here than strchr(), then you
don't need to deal with the *line = '\0'.
> + }
> +
> + guest->next = handle->guest;
> + handle->guest = guest;
> + return 0;
> +
> +error:
> + if (guest) {
> + free(guest->cpu_pid);
> + free(guest->name);
> + free(guest);
> + }
> + return -1;
> +}
> +
> #define STR_PROCMAP_LINE_MAX (PATH_MAX+22)
> static int trace_pid_map_load(struct tracecmd_input *handle, char *buf)
> {
> @@ -2558,6 +2634,10 @@ static int handle_options(struct tracecmd_input *handle)
> if (buf[size-1] == '\0')
> trace_traceid_load(handle, buf);
> break;
> + case TRACECMD_OPTION_GUEST:
> + if (buf[size-1] == '\0')
> + trace_guest_load(handle, buf);
> + break;
> default:
> warning("unknown option %d", option);
> break;
> @@ -3217,6 +3297,7 @@ void tracecmd_close(struct tracecmd_input *handle)
> handle->pid_maps = NULL;
>
> trace_tsync_offset_free(&handle->host);
> + trace_guests_free(handle);
>
> if (handle->flags & TRACECMD_FL_BUFFER_INSTANCE)
> tracecmd_close(handle->parent);
> @@ -3673,6 +3754,38 @@ unsigned long long tracecmd_get_traceid(struct tracecmd_input *handle)
> return handle->trace_id;
> }
>
> +/**
> + * tracecmd_get_guest_cpumap - get the mapping of guest VCPU to host process
> + * @handle: input handle for the trace.dat file
> + * @trace_id: ID of the guest tracing session
@name, @vcpu_count, and @cpu_pid should still be up in the above
section.
> + *
> + * Returns @name of the guest, number of VPUs (@vcpu_count)
> + * and array @cpu_pid with size @vcpu_count. Array index is VCPU id, array
> + * content is PID of the host process, running this VCPU.
> + *
> + * This information is stored in host trace.dat file
> + */
> +int tracecmd_get_guest_cpumap(struct tracecmd_input *handle,
> + unsigned long long trace_id,
> + char *name,
name isn't returned.
> + int *vcpu_count, int *cpu_pid)
> +{
> + struct guest_trace_info *guest = handle->guest;
> +
> + while (guest) {
> + if (guest->trace_id == trace_id)
> + break;
> + guest = guest->next;
> + }
> + if (!guest)
> + return -1;
> +
> + name = guest->name;
The above doesn't do anything, and will probably be optimized out by
the compiler.
-- Steve
> + *vcpu_count = guest->vcpu_count;
> + cpu_pid = guest->cpu_pid;
> + return 0;
> +}
> +
> /**
> * tracecmd_get_tsync_peer - get the trace session id of the peer host
> * @handle: input handle for the trace.dat file
> diff --git a/tracecmd/trace-record.c b/tracecmd/trace-record.c
> index e51134f..49730d6 100644
> --- a/tracecmd/trace-record.c
> +++ b/tracecmd/trace-record.c
> @@ -2884,6 +2884,19 @@ struct guest {
> static struct guest *guests;
> static size_t guests_len;
>
> +static struct guest *get_guest_info(unsigned int guest_cid)
> +{
> + int i;
> +
> + if (!guests)
> + return NULL;
> +
> + for (i = 0; i < guests_len; i++)
> + if (guest_cid == guests[i].cid)
> + return guests + i;
> + return NULL;
> +}
> +
> static char *get_qemu_guest_name(char *arg)
> {
> char *tok, *end = arg;
> @@ -3689,6 +3702,33 @@ static void append_buffer(struct tracecmd_output *handle,
> }
> }
>
> +static void
> +add_guest_info(struct tracecmd_output *handle, struct buffer_instance *instance)
> +{
> + struct guest *guest = get_guest_info(instance->cid);
> + struct trace_seq s;
> + int i;
> +
> + if (!guest)
> + return;
> + for (i = 0; i < VCPUS_MAX; i++)
> + if (!guest->cpu_pid[i])
> + break;
> +
> + trace_seq_init(&s);
> +
> + trace_seq_printf(&s, "Guest %s %llu %d\n",
> + guest->name, instance->trace_id, i);
> + for (i = 0; i < VCPUS_MAX; i++) {
> + if (!guest->cpu_pid[i])
> + break;
> + trace_seq_printf(&s, "%d %d\n", i, guest->cpu_pid[i]);
> + }
> + trace_seq_terminate(&s);
> + tracecmd_add_option(handle, TRACECMD_OPTION_GUEST,
> + s.len + 1, s.buffer);
> + trace_seq_destroy(&s);
> +}
>
> static void
> add_pid_maps(struct tracecmd_output *handle, struct buffer_instance *instance)
> @@ -3976,6 +4016,11 @@ static void record_data(struct common_record_context *ctx)
> add_pid_maps(handle, instance);
> }
>
> + for_all_instances(instance) {
> + if (is_guest(instance))
> + add_guest_info(handle, instance);
> + }
> +
> tracecmd_append_cpu_data(handle, local_cpu_count, temp_files);
>
> for (i = 0; i < max_cpu_count; i++)
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