[lttng-dev] [UST PATCH 2/2] LTTng ringbuffer ABI calls for index generation

Mathieu Desnoyers mathieu.desnoyers at efficios.com
Thu Aug 15 17:52:55 EDT 2013


* Julien Desfossez (jdesfossez at efficios.com) wrote:
> These new calls export the data required for the consumer to
> generate the index while tracing :
> - timestamp begin
> - timestamp end
> - events discarded
> - context size
> - packet size
> - stream id
> 
> Signed-off-by: Julien Desfossez <jdesfossez at efficios.com>
> ---
>  include/lttng/ust-ctl.h                 |   14 ++++
>  liblttng-ust-ctl/ustctl.c               |   90 ++++++++++++++++++++++
>  liblttng-ust/lttng-rb-clients.h         |   19 +++++
>  liblttng-ust/lttng-ring-buffer-client.h |   91 ++++++++++++++++++++++
>  libringbuffer/frontend.h                |   19 +++++
>  libringbuffer/ring_buffer_frontend.c    |  127 +++++++++++++++++++++++++++++++
>  6 files changed, 360 insertions(+)
> 
> diff --git a/include/lttng/ust-ctl.h b/include/lttng/ust-ctl.h
> index 3c81e50..88112ad 100644
> --- a/include/lttng/ust-ctl.h
> +++ b/include/lttng/ust-ctl.h
> @@ -220,6 +220,20 @@ int ustctl_put_subbuf(struct ustctl_consumer_stream *stream);
>  void ustctl_flush_buffer(struct ustctl_consumer_stream *stream,
>  		int producer_active);
>  
> +/* index */
> +int ustctl_get_timestamp_begin(struct ustctl_consumer_stream *stream,
> +		uint64_t *timestamp_begin);
> +int ustctl_get_timestamp_end(struct ustctl_consumer_stream *stream,
> +	uint64_t *timestamp_end);
> +int ustctl_get_events_discarded(struct ustctl_consumer_stream *stream,
> +	uint64_t *events_discarded);
> +int ustctl_get_content_size(struct ustctl_consumer_stream *stream,
> +	uint64_t *content_size);
> +int ustctl_get_packet_size(struct ustctl_consumer_stream *stream,
> +	uint64_t *packet_size);
> +int ustctl_get_stream_id(struct ustctl_consumer_stream *stream,
> +		uint64_t *stream_id);
> +
>  /* event registry management */
>  
>  enum ustctl_socket_type {
> diff --git a/liblttng-ust-ctl/ustctl.c b/liblttng-ust-ctl/ustctl.c
> index 28dee5e..a53ba3f 100644
> --- a/liblttng-ust-ctl/ustctl.c
> +++ b/liblttng-ust-ctl/ustctl.c
> @@ -1461,6 +1461,96 @@ void ustctl_flush_buffer(struct ustctl_consumer_stream *stream,
>  		consumer_chan->chan->handle);
>  }
>  
> +int ustctl_get_timestamp_begin(struct ustctl_consumer_stream *stream,
> +		uint64_t *timestamp_begin)
> +{
> +	struct lttng_ust_lib_ring_buffer *buf;
> +	struct ustctl_consumer_channel *consumer_chan;
> +
> +	if (!stream)
> +		return -EINVAL;
> +	buf = stream->buf;
> +	consumer_chan = stream->chan;
> +
> +	return lib_ring_buffer_get_timestamp_begin(buf, consumer_chan->chan->handle,
> +			timestamp_begin);

these should not call a lib_ring_buffer function to do
get_timestamp_begin, but rather call a callback specific to the client.
It should test if the callback is NULL and return an error if it is (in
the case the stream is a metadata stream).

> +}
> +
> +int ustctl_get_timestamp_end(struct ustctl_consumer_stream *stream,
> +	uint64_t *timestamp_end)
> +{
> +	struct lttng_ust_lib_ring_buffer *buf;
> +	struct ustctl_consumer_channel *consumer_chan;
> +
> +	if (!stream)
> +		return -EINVAL;
> +	buf = stream->buf;
> +	consumer_chan = stream->chan;
> +
> +	return lib_ring_buffer_get_timestamp_end(buf, consumer_chan->chan->handle,
> +			timestamp_end);
> +}
> +
> +int ustctl_get_events_discarded(struct ustctl_consumer_stream *stream,
> +	uint64_t *events_discarded)
> +{
> +	struct lttng_ust_lib_ring_buffer *buf;
> +	struct ustctl_consumer_channel *consumer_chan;
> +
> +	if (!stream)
> +		return -EINVAL;
> +	buf = stream->buf;
> +	consumer_chan = stream->chan;
> +
> +	return lib_ring_buffer_get_events_discarded(buf, consumer_chan->chan->handle,
> +			events_discarded);
> +}
> +
> +int ustctl_get_content_size(struct ustctl_consumer_stream *stream,
> +	uint64_t *content_size)
> +{
> +	struct lttng_ust_lib_ring_buffer *buf;
> +	struct ustctl_consumer_channel *consumer_chan;
> +
> +	if (!stream)
> +		return -EINVAL;
> +	buf = stream->buf;
> +	consumer_chan = stream->chan;
> +
> +	return lib_ring_buffer_get_content_size(buf, consumer_chan->chan->handle,
> +			content_size);
> +}
> +
> +int ustctl_get_packet_size(struct ustctl_consumer_stream *stream,
> +	uint64_t *packet_size)
> +{
> +	struct lttng_ust_lib_ring_buffer *buf;
> +	struct ustctl_consumer_channel *consumer_chan;
> +
> +	if (!stream)
> +		return -EINVAL;
> +	buf = stream->buf;
> +	consumer_chan = stream->chan;
> +
> +	return lib_ring_buffer_get_packet_size(buf, consumer_chan->chan->handle,
> +			packet_size);
> +}
> +
> +int ustctl_get_stream_id(struct ustctl_consumer_stream *stream,
> +		uint64_t *stream_id)
> +{
> +	struct lttng_ust_lib_ring_buffer *buf;
> +	struct ustctl_consumer_channel *consumer_chan;
> +
> +	if (!stream)
> +		return -EINVAL;
> +	buf = stream->buf;
> +	consumer_chan = stream->chan;
> +
> +	return lib_ring_buffer_get_stream_id(buf, consumer_chan->chan->handle,
> +			stream_id);
> +}
> +
>  /*
>   * Returns 0 on success, negative error value on error.
>   */
> diff --git a/liblttng-ust/lttng-rb-clients.h b/liblttng-ust/lttng-rb-clients.h
> index 37fd842..3a22e03 100644
> --- a/liblttng-ust/lttng-rb-clients.h
> +++ b/liblttng-ust/lttng-rb-clients.h
> @@ -3,6 +3,25 @@
>  
>  struct specialized_lttng_ust_lib_ring_buffer_client_cb {
>  	struct lttng_ust_lib_ring_buffer_client_cb parent;
> +
> +	int (*timestamp_begin) (struct lttng_ust_lib_ring_buffer *buf,
> +			struct lttng_ust_shm_handle *handle,
> +			uint64_t *timestamp_begin);
> +	int (*timestamp_end) (struct lttng_ust_lib_ring_buffer *buf,
> +			struct lttng_ust_shm_handle *handle,
> +			uint64_t *timestamp_end);
> +	int (*events_discarded) (struct lttng_ust_lib_ring_buffer *buf,
> +			struct lttng_ust_shm_handle *handle,
> +			uint64_t *events_discarded);
> +	int (*content_size) (struct lttng_ust_lib_ring_buffer *buf,
> +			struct lttng_ust_shm_handle *handle,
> +			uint64_t *content_size);
> +	int (*packet_size) (struct lttng_ust_lib_ring_buffer *buf,
> +			struct lttng_ust_shm_handle *handle,
> +			uint64_t *packet_size);
> +	int (*stream_id) (struct lttng_ust_lib_ring_buffer *buf,
> +			struct lttng_ust_shm_handle *handle,
> +			uint64_t *stream_id);
>  };
>  
>  #endif /* _LTTNG_RB_CLIENT_H */
> diff --git a/liblttng-ust/lttng-ring-buffer-client.h b/liblttng-ust/lttng-ring-buffer-client.h
> index 94db97e..942a624 100644
> --- a/liblttng-ust/lttng-ring-buffer-client.h
> +++ b/liblttng-ust/lttng-ring-buffer-client.h
> @@ -386,6 +386,91 @@ static void client_buffer_finalize(struct lttng_ust_lib_ring_buffer *buf, void *
>  {
>  }
>  
> +static struct packet_header *client_packet_header(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle)
> +{
> +	struct channel *chan = shmp(handle, buf->backend.chan);
> +	struct lttng_channel *lttng_chan = channel_get_private(chan);
> +	unsigned long sb_index;
> +	struct lttng_ust_lib_ring_buffer_backend *bufb;
> +	struct packet_header *header;
> +
> +	bufb = &buf->backend;
> +	sb_index = subbuffer_id_get_index(&lttng_chan->chan->backend.config,
> +			bufb->buf_rsb.id);
> +
> +	header = lib_ring_buffer_offset_address(bufb,
> +			sb_index * lttng_chan->chan->backend.subbuf_size,
> +			handle);
> +
> +	return header;
> +}
> +
> +static int client_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *timestamp_begin)
> +{
> +	struct packet_header *header = client_packet_header(buf, handle);
> +
> +	*timestamp_begin = header->ctx.timestamp_begin;
> +
> +	return 0;
> +}
> +
> +static int client_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *timestamp_end)
> +{
> +	struct packet_header *header = client_packet_header(buf, handle);
> +
> +	*timestamp_end = header->ctx.timestamp_end;
> +
> +	return 0;
> +}
> +
> +static int client_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *events_discarded)
> +{
> +	struct packet_header *header = client_packet_header(buf, handle);
> +
> +	*events_discarded = header->ctx.events_discarded;
> +
> +	return 0;
> +}
> +
> +static int client_content_size(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *content_size)
> +{
> +	struct packet_header *header = client_packet_header(buf, handle);
> +
> +	*content_size = header->ctx.content_size;
> +
> +	return 0;
> +}
> +
> +static int client_packet_size(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *packet_size)
> +{
> +	struct packet_header *header = client_packet_header(buf, handle);
> +
> +	*packet_size = header->ctx.packet_size;
> +
> +	return 0;
> +}
> +
> +static int client_stream_id(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *stream_id)
> +{
> +	struct packet_header *header = client_packet_header(buf, handle);
> +
> +	*stream_id = header->stream_id;
> +
> +	return 0;
> +}
>  static const
>  struct specialized_lttng_ust_lib_ring_buffer_client_cb client_cb = {
>  	.parent = {
> @@ -397,6 +482,12 @@ struct specialized_lttng_ust_lib_ring_buffer_client_cb client_cb = {
>  		.buffer_create = client_buffer_create,
>  		.buffer_finalize = client_buffer_finalize,
>  	},
> +	.timestamp_begin = client_timestamp_begin,
> +	.timestamp_end = client_timestamp_end,
> +	.events_discarded = client_events_discarded,
> +	.content_size = client_content_size,
> +	.packet_size = client_packet_size,
> +	.stream_id = client_stream_id,
>  };
>  
>  static const struct lttng_ust_lib_ring_buffer_config client_config = {
> diff --git a/libringbuffer/frontend.h b/libringbuffer/frontend.h
> index 89613d4..92399d2 100644
> --- a/libringbuffer/frontend.h
> +++ b/libringbuffer/frontend.h
> @@ -269,4 +269,23 @@ unsigned long lib_ring_buffer_get_records_read(
>  	return v_read(config, &buf->backend.records_read);
>  }
>  

All the per-client stuff don't belong in the frontend.h file. This is
specific to the lttng ring buffer client.

> +extern int lib_ring_buffer_get_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *timestamp_begin);
> +extern int lib_ring_buffer_get_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *timestamp_end);
> +extern int lib_ring_buffer_get_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *events_discarded);
> +extern int lib_ring_buffer_get_content_size(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *content_size);
> +extern int lib_ring_buffer_get_packet_size(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *packet_size);
> +extern int lib_ring_buffer_get_stream_id(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *stream_id);
> +
>  #endif /* _LTTNG_RING_BUFFER_FRONTEND_H */
> diff --git a/libringbuffer/ring_buffer_frontend.c b/libringbuffer/ring_buffer_frontend.c
> index e99ba8a..6664935 100644
> --- a/libringbuffer/ring_buffer_frontend.c
> +++ b/libringbuffer/ring_buffer_frontend.c

The stuff below should be moved to the lttng ringbuffer client file.

Thanks,

Mathieu

> @@ -72,6 +72,7 @@
>  #include "shm.h"
>  #include "tlsfixup.h"
>  #include "../liblttng-ust/compat.h"	/* For ENODATA */
> +#include "../liblttng-ust/lttng-rb-clients.h"
>  
>  #ifndef max
>  #define max(a, b)	((a) > (b) ? (a) : (b))
> @@ -1869,6 +1870,132 @@ int lib_ring_buffer_reserve_slow(struct lttng_ust_lib_ring_buffer_ctx *ctx)
>  	return 0;
>  }
>  
> +/**
> + * lib_ring_buffer_get_timestamp_begin - get the timestamp begin of the subbuffer
> + * @buf: ring buffer
> + * @timestamp_begin: timestamp begin of the subbuffer
> + *
> + * Returns 0 on success, a negative value on error.
> + */
> +int lib_ring_buffer_get_timestamp_begin(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *timestamp_begin)
> +{
> +	struct channel *chan = shmp(handle, buf->backend.chan);
> +	const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
> +	struct specialized_lttng_ust_lib_ring_buffer_client_cb *client_cb;
> +
> +	client_cb = caa_container_of(config->cb_ptr,
> +			struct specialized_lttng_ust_lib_ring_buffer_client_cb,
> +			parent);
> +	return client_cb->timestamp_begin(buf, handle, timestamp_begin);
> +}
> +
> +/**
> + * lib_ring_buffer_get_timestamp_end - get the timestamp end of the subbuffer
> + * @buf: ring buffer
> + * @timestamp_end: timestamp end of the subbuffer
> + *
> + * Returns 0 on success, a negative value on error.
> + */
> +int lib_ring_buffer_get_timestamp_end(struct lttng_ust_lib_ring_buffer *buf,
> +	struct lttng_ust_shm_handle *handle,
> +	uint64_t *timestamp_end)
> +{
> +	struct channel *chan = shmp(handle, buf->backend.chan);
> +	const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
> +	struct specialized_lttng_ust_lib_ring_buffer_client_cb *client_cb;
> +
> +	client_cb = caa_container_of(config->cb_ptr,
> +			struct specialized_lttng_ust_lib_ring_buffer_client_cb,
> +			parent);
> +	return client_cb->timestamp_end(buf, handle, timestamp_end);
> +}
> +
> +/**
> + * lib_ring_buffer_get_events_discarded - get the number of discarded events
> + * @buf: ring buffer
> + * @events_discarded: discarded events
> + *
> + * Returns 0 on success, a negative value on error.
> + */
> +int lib_ring_buffer_get_events_discarded(struct lttng_ust_lib_ring_buffer *buf,
> +	struct lttng_ust_shm_handle *handle,
> +	uint64_t *events_discarded)
> +{
> +	struct channel *chan = shmp(handle, buf->backend.chan);
> +	const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
> +	struct specialized_lttng_ust_lib_ring_buffer_client_cb *client_cb;
> +
> +	client_cb = caa_container_of(config->cb_ptr,
> +			struct specialized_lttng_ust_lib_ring_buffer_client_cb,
> +			parent);
> +	return client_cb->events_discarded(buf, handle, events_discarded);
> +}
> +
> +/**
> + * lib_ring_buffer_get_content_size - get the content size of the subbuffer
> + * @buf: ring buffer
> + * @content_size: content size of the subbuffer
> + *
> + * Returns 0 on success, a negative value on error.
> + */
> +int lib_ring_buffer_get_content_size(struct lttng_ust_lib_ring_buffer *buf,
> +	struct lttng_ust_shm_handle *handle,
> +	uint64_t *content_size)
> +{
> +	struct channel *chan = shmp(handle, buf->backend.chan);
> +	const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
> +	struct specialized_lttng_ust_lib_ring_buffer_client_cb *client_cb;
> +
> +	client_cb = caa_container_of(config->cb_ptr,
> +			struct specialized_lttng_ust_lib_ring_buffer_client_cb,
> +			parent);
> +	return client_cb->content_size(buf, handle, content_size);
> +}
> +
> +/**
> + * lib_ring_buffer_get_packet_size - get the packet size of the subbuffer
> + * @buf: ring buffer
> + * @packet_size: packet size of the subbuffer
> + *
> + * Returns 0 on success, a negative value on error.
> + */
> +int lib_ring_buffer_get_packet_size(struct lttng_ust_lib_ring_buffer *buf,
> +	struct lttng_ust_shm_handle *handle,
> +	uint64_t *packet_size)
> +{
> +	struct channel *chan = shmp(handle, buf->backend.chan);
> +	const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
> +	struct specialized_lttng_ust_lib_ring_buffer_client_cb *client_cb;
> +
> +	client_cb = caa_container_of(config->cb_ptr,
> +			struct specialized_lttng_ust_lib_ring_buffer_client_cb,
> +			parent);
> +	return client_cb->packet_size(buf, handle, packet_size);
> +}
> +
> +/**
> + * lib_ring_buffer_get_stream_id - get the strean ID of the subbuffer
> + * @buf: ring buffer
> + * @stream_id: stream ID of the subbuffer
> + *
> + * Returns 0 on success, a negative value on error.
> + */
> +int lib_ring_buffer_get_stream_id(struct lttng_ust_lib_ring_buffer *buf,
> +		struct lttng_ust_shm_handle *handle,
> +		uint64_t *stream_id)
> +{
> +	struct channel *chan = shmp(handle, buf->backend.chan);
> +	const struct lttng_ust_lib_ring_buffer_config *config = &chan->backend.config;
> +	struct specialized_lttng_ust_lib_ring_buffer_client_cb *client_cb;
> +
> +	client_cb = caa_container_of(config->cb_ptr,
> +			struct specialized_lttng_ust_lib_ring_buffer_client_cb,
> +			parent);
> +	return client_cb->stream_id(buf, handle, stream_id);
> +}
> +
>  /*
>   * Force a read (imply TLS fixup for dlopen) of TLS variables.
>   */
> -- 
> 1.7.10.4
> 

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com



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