On Fri, 10 Dec 2021 12:54:41 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:
The "space police" are back!
> The BUFFER option is extended in trace file version 7. It holds CPU
> metadata related to the recorded CPU traces. Also, there is a new
> BUFFER_TEXT option for describing the latency trace data. A new logic
> is implemented for these new options.
space
> In trace file version 7, the top buffer is saved as other buffers in the
> file, no special treatment. But saving the top buffer in the list of
> buffers in the input handler causes problems. It breaks the legacy logic
> of trace-cmd library users, which have special logic for trace buffers
> processing. That's why "top_buffer" member is added in the input handler
> structure, to hold the top buffer.
>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
> ---
> lib/trace-cmd/trace-input.c | 139 +++++++++++++++++++++++++++++++-----
> 1 file changed, 122 insertions(+), 17 deletions(-)
>
> diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
> index 6cc8ee90..5625e367 100644
> --- a/lib/trace-cmd/trace-input.c
> +++ b/lib/trace-cmd/trace-input.c
> @@ -74,9 +74,19 @@ struct cpu_data {
> int pipe_fd;
> };
>
> +struct cpu_file_data {
> + int cpu;
> + unsigned long long offset;
> + unsigned long long size;
> +};
> +
> struct input_buffer_instance {
> char *name;
> size_t offset;
> + char *clock;
> + bool latency;
> + int cpus;
> + struct cpu_file_data *cpu_data;
> };
>
> struct ts_offset_sample {
> @@ -156,6 +166,7 @@ struct tracecmd_input {
> char * uname;
> char * version;
> char * trace_clock;
> + struct input_buffer_instance top_buffer;
> struct input_buffer_instance *buffers;
> int parsing_failures;
> struct guest_trace_info *guest;
> @@ -2857,13 +2868,109 @@ __hidden unsigned int get_meta_strings_size(struct tracecmd_input *handle)
> return handle->strings_size;
> }
>
> +static inline int save_read_number(struct tep_handle *tep, char *data, int *data_size,
> + int *read_pos, int bytes, unsigned long long *num)
> +{
> + if (bytes > *data_size)
> + return -1;
space
> + *num = tep_read_number(tep, (data + *read_pos), bytes);
> + *read_pos += bytes;
> + *data_size -= bytes;
> + return 0;
> +}
> +
> +static inline char *save_read_string(char *data, int *data_size, int *read_pos)
> +{
> + char *str;
> +
> + if (*data_size < 1)
> + return NULL;
space
> + str = strdup(data + *read_pos);
> + if (!str)
> + return NULL;
space
> + *data_size -= (strlen(str) + 1);
> + if (*data_size < 0) {
> + free(str);
> + return NULL;
> + }
space
> + *read_pos += (strlen(str) + 1);
> +
> + return str;
> +}
> +
> +static int handle_buffer_option(struct tracecmd_input *handle,
> + unsigned short id, char *data, int size)
> +{
> + struct input_buffer_instance *buff;
> + unsigned long long tmp;
> + int rsize = 0;
> + char *name;
> + int i;
> +
> + if (save_read_number(handle->pevent, data, &size, &rsize, 8, &tmp))
> + return -1;
space
> + name = save_read_string(data, &size, &rsize);
> + if (!name)
> + return -1;
> +
> + if (*name == '\0') {
> + /* top buffer */
> + buff = &handle->top_buffer;
> + } else {
> + buff = realloc(handle->buffers, sizeof(*handle->buffers) * (handle->nr_buffers + 1));
> + if (!buff) {
> + free(name);
> + return -1;
> + }
> + handle->buffers = buff;
> + handle->nr_buffers++;
> +
> + buff = &handle->buffers[handle->nr_buffers - 1];
> + }
> + memset(buff, 0, sizeof(struct input_buffer_instance));
> + buff->name = name;
> + buff->offset = tmp;
space
> + if (!HAS_SECTIONS(handle))
> + return 0;
> +
> + /* file sections specific data */
> + buff->clock = save_read_string(data, &size, &rsize);
> + if (!buff->clock)
> + return -1;
space
> + if (*name == '\0' && !handle->trace_clock)
> + handle->trace_clock = strdup(buff->clock);
space
> + if (id == TRACECMD_OPTION_BUFFER) {
> + if (save_read_number(handle->pevent, data, &size, &rsize, 4, &tmp))
> + return -1;
> + buff->cpus = tmp;
> + if (!buff->cpus)
> + return 0;
> + buff->cpu_data = calloc(buff->cpus, sizeof(struct cpu_file_data));
> + if (!buff->cpu_data)
> + return -1;
> + for (i = 0; i < buff->cpus; i++) {
> + if (save_read_number(handle->pevent, data, &size, &rsize, 4, &tmp))
> + return -1;
> + buff->cpu_data[i].cpu = tmp;
> + if (save_read_number(handle->pevent, data,
> + &size, &rsize, 8, &buff->cpu_data[i].offset))
> + return -1;
> + if (save_read_number(handle->pevent, data,
> + &size, &rsize, 8, &buff->cpu_data[i].size))
> + return -1;
> + }
> + } else {
> + buff->latency = true;
> + }
> + return 0;
> +}
> +
-- Steve
> static int handle_options(struct tracecmd_input *handle)
> {
> long long offset;
> unsigned short option;
> unsigned int size;
> char *cpustats = NULL;
> - struct input_buffer_instance *buffer;
> struct hook_list *hook;
> char *buf;
> int cpus;
> @@ -2954,21 +3061,10 @@ static int handle_options(struct tracecmd_input *handle)
> handle->cpustats = cpustats;
> break;
> case TRACECMD_OPTION_BUFFER:
> - /* A buffer instance is saved at the end of the file */
> - handle->nr_buffers++;
> - handle->buffers = realloc(handle->buffers,
> - sizeof(*handle->buffers) * handle->nr_buffers);
> - if (!handle->buffers)
> - return -ENOMEM;
> - buffer = &handle->buffers[handle->nr_buffers - 1];
> - buffer->name = strdup(buf + 8);
> - if (!buffer->name) {
> - free(handle->buffers);
> - handle->buffers = NULL;
> - return -ENOMEM;
> - }
> - offset = *(unsigned long long *)buf;
> - buffer->offset = tep_read_number(handle->pevent, &offset, 8);
> + case TRACECMD_OPTION_BUFFER_TEXT:
> + ret = handle_buffer_option(handle, option, buf, size);
> + if (ret < 0)
> + return ret;
> break;
> case TRACECMD_OPTION_TRACECLOCK:
> if (!handle->ts2secs)
> @@ -3757,6 +3853,13 @@ void tracecmd_ref(struct tracecmd_input *handle)
> handle->ref++;
> }
>
> +static inline void free_buffer(struct input_buffer_instance *buf)
> +{
> + free(buf->name);
> + free(buf->clock);
> + free(buf->cpu_data);
> +}
> +
> /**
> * tracecmd_close - close and free the trace.dat handle
> * @handle: input handle for the trace.dat file
> @@ -3813,8 +3916,9 @@ void tracecmd_close(struct tracecmd_input *handle)
> free(del_sec);
> }
>
> + free_buffer(&handle->top_buffer);
> for (i = 0; i < handle->nr_buffers; i++)
> - free(handle->buffers[i].name);
> + free_buffer(&handle->buffers[i]);
> free(handle->buffers);
>
> tracecmd_free_hooks(handle->hooks);
> @@ -4258,6 +4362,7 @@ tracecmd_buffer_instance_handle(struct tracecmd_input *handle, int indx)
> return NULL;
>
> *new_handle = *handle;
> + memset(&new_handle->top_buffer, 0, sizeof(new_handle->top_buffer));
> new_handle->cpu_data = NULL;
> new_handle->nr_buffers = 0;
> new_handle->buffers = NULL;
|