Maximum size in bytes of the snapshot. The maximum size does not include the
metadata file. Human readable format is accepted: {+k,+M,+G}. For instance,
\-\-max-size 5M
-
-The minimum size of a snapshot is computed by multiplying the total amount of
-streams in the session by the largest subbuffer size. This is to ensure
-fairness between channels when extracting data.
.TP
.BR "\-C, \-\-ctrl-url URL"
Set control path URL. (Must use -D also)
struct lttng_ht_node_u64 node;
/* Size of subbuffers in this channel. */
size_t subbuf_size;
+ /* Number of subbuffers per stream. */
+ size_t num_subbuf;
union {
/* Original object data that MUST be copied over. */
struct lttng_ust_object_data *ust;
*/
static int record_kernel_snapshot(struct ltt_kernel_session *ksess,
struct snapshot_output *output, struct ltt_session *session,
- int wait, uint64_t max_stream_size)
+ int wait, uint64_t nb_packets_per_stream)
{
int ret;
goto error_snapshot;
}
- ret = kernel_snapshot_record(ksess, output, wait, max_stream_size);
+ ret = kernel_snapshot_record(ksess, output, wait, nb_packets_per_stream);
if (ret != LTTNG_OK) {
goto error_snapshot;
}
*/
static int record_ust_snapshot(struct ltt_ust_session *usess,
struct snapshot_output *output, struct ltt_session *session,
- int wait, uint64_t max_stream_size)
+ int wait, uint64_t nb_packets_per_stream)
{
int ret;
goto error_snapshot;
}
- ret = ust_app_snapshot_record(usess, output, wait, max_stream_size);
+ ret = ust_app_snapshot_record(usess, output, wait, nb_packets_per_stream);
if (ret < 0) {
switch (-ret) {
case EINVAL:
return ret;
}
-/*
- * Return the biggest subbuffer size of all channels in the given session.
- */
-static uint64_t get_session_max_subbuf_size(struct ltt_session *session)
+static
+uint64_t get_session_size_one_more_packet_per_stream(struct ltt_session *session,
+ uint64_t cur_nr_packets)
{
- uint64_t max_size = 0;
-
- assert(session);
+ uint64_t tot_size = 0;
if (session->kernel_session) {
struct ltt_kernel_channel *chan;
struct ltt_kernel_session *ksess = session->kernel_session;
- /*
- * For each channel, add to the max size the size of each subbuffer
- * multiplied by their sized.
- */
cds_list_for_each_entry(chan, &ksess->channel_list.head, list) {
- if (chan->channel->attr.subbuf_size > max_size) {
- max_size = chan->channel->attr.subbuf_size;
+ if (cur_nr_packets >= chan->channel->attr.num_subbuf) {
+ /*
+ * Don't take channel into account if we
+ * already grab all its packets.
+ */
+ continue;
}
+ tot_size += chan->channel->attr.subbuf_size
+ * chan->stream_count;
}
}
if (session->ust_session) {
- struct lttng_ht_iter iter;
- struct ltt_ust_channel *uchan;
struct ltt_ust_session *usess = session->ust_session;
- rcu_read_lock();
- cds_lfht_for_each_entry(usess->domain_global.channels->ht, &iter.iter,
- uchan, node.node) {
- if (uchan->attr.subbuf_size > max_size) {
- max_size = uchan->attr.subbuf_size;
- }
- }
- rcu_read_unlock();
+ tot_size += ust_app_get_size_one_more_packet_per_stream(usess,
+ cur_nr_packets);
}
- return max_size;
+ return tot_size;
}
/*
- * Returns the total number of streams for a session or a negative value
- * on error.
+ * Calculate the number of packets we can grab from each stream that
+ * fits within the overall snapshot max size.
+ *
+ * Returns -1 on error, 0 means infinite number of packets, else > 0 is
+ * the number of packets per stream.
+ *
+ * TODO: this approach is not perfect: we consider the worse case
+ * (packet filling the sub-buffers) as an upper bound, but we could do
+ * better if we do this calculation while we actually grab the packet
+ * content: we would know how much padding we don't actually store into
+ * the file.
+ *
+ * This algorithm is currently bounded by the number of packets per
+ * stream.
+ *
+ * Since we call this algorithm before actually grabbing the data, it's
+ * an approximation: for instance, applications could appear/disappear
+ * in between this call and actually grabbing data.
*/
-static unsigned int get_session_nb_streams(struct ltt_session *session)
+static
+int64_t get_session_nb_packets_per_stream(struct ltt_session *session, uint64_t max_size)
{
- unsigned int total_streams = 0;
-
- if (session->kernel_session) {
- struct ltt_kernel_session *ksess = session->kernel_session;
+ int64_t size_left;
+ uint64_t cur_nb_packets = 0;
- total_streams += ksess->stream_count_global;
+ if (!max_size) {
+ return 0; /* Infinite */
}
- if (session->ust_session) {
- struct ltt_ust_session *usess = session->ust_session;
+ size_left = max_size;
+ for (;;) {
+ uint64_t one_more_packet_tot_size;
- total_streams += ust_app_get_nb_stream(usess);
+ one_more_packet_tot_size = get_session_size_one_more_packet_per_stream(session,
+ cur_nb_packets);
+ if (!one_more_packet_tot_size) {
+ /* We are already grabbing all packets. */
+ break;
+ }
+ size_left -= one_more_packet_tot_size;
+ if (size_left < 0) {
+ break;
+ }
+ cur_nb_packets++;
}
-
- return total_streams;
+ if (!cur_nb_packets) {
+ /* Not enough room to grab one packet of each stream, error. */
+ return -1;
+ }
+ return cur_nb_packets;
}
/*
unsigned int use_tmp_output = 0;
struct snapshot_output tmp_output;
unsigned int nb_streams, snapshot_success = 0;
- uint64_t session_max_size = 0, max_stream_size = 0;
assert(session);
assert(output);
use_tmp_output = 1;
}
- /*
- * Get the session maximum size for a snapshot meaning it will compute the
- * size of all streams from all domain.
- */
- max_stream_size = get_session_max_subbuf_size(session);
-
- nb_streams = get_session_nb_streams(session);
- if (nb_streams) {
- /*
- * The maximum size of the snapshot is the number of streams multiplied
- * by the biggest subbuf size of all channels in a session which is the
- * maximum stream size available for each stream. The session max size
- * is now checked against the snapshot max size value given by the user
- * and if lower, an error is returned.
- */
- session_max_size = max_stream_size * nb_streams;
- }
-
- DBG3("Snapshot max size is %" PRIu64 " for max stream size of %" PRIu64,
- session_max_size, max_stream_size);
-
- /*
- * If we use a temporary output, check right away if the max size fits else
- * for each output the max size will be checked.
- */
- if (use_tmp_output &&
- (tmp_output.max_size != 0 &&
- tmp_output.max_size < session_max_size)) {
- ret = LTTNG_ERR_MAX_SIZE_INVALID;
- goto error;
- }
-
if (session->kernel_session) {
struct ltt_kernel_session *ksess = session->kernel_session;
if (use_tmp_output) {
+ int64_t nb_packets_per_stream;
+
+ nb_packets_per_stream = get_session_nb_packets_per_stream(session,
+ tmp_output.max_size);
+ if (nb_packets_per_stream < 0) {
+ ret = LTTNG_ERR_MAX_SIZE_INVALID;
+ goto error;
+ }
ret = record_kernel_snapshot(ksess, &tmp_output, session,
- wait, max_stream_size);
+ wait, nb_packets_per_stream);
if (ret != LTTNG_OK) {
goto error;
}
rcu_read_lock();
cds_lfht_for_each_entry(session->snapshot.output_ht->ht,
&iter.iter, sout, node.node) {
+ int64_t nb_packets_per_stream;
+
/*
* Make a local copy of the output and assign the possible
* temporary value given by the caller.
memset(&tmp_output, 0, sizeof(tmp_output));
memcpy(&tmp_output, sout, sizeof(tmp_output));
- /* Use temporary max size. */
if (output->max_size != (uint64_t) -1ULL) {
tmp_output.max_size = output->max_size;
}
- if (tmp_output.max_size != 0 &&
- tmp_output.max_size < session_max_size) {
- rcu_read_unlock();
+ nb_packets_per_stream = get_session_nb_packets_per_stream(session,
+ tmp_output.max_size);
+ if (nb_packets_per_stream < 0) {
ret = LTTNG_ERR_MAX_SIZE_INVALID;
goto error;
}
tmp_output.nb_snapshot = session->snapshot.nb_snapshot;
ret = record_kernel_snapshot(ksess, &tmp_output,
- session, wait, max_stream_size);
+ session, wait, nb_packets_per_stream);
if (ret != LTTNG_OK) {
rcu_read_unlock();
goto error;
struct ltt_ust_session *usess = session->ust_session;
if (use_tmp_output) {
+ int64_t nb_packets_per_stream;
+
+ nb_packets_per_stream = get_session_nb_packets_per_stream(session,
+ tmp_output.max_size);
+ if (nb_packets_per_stream < 0) {
+ ret = LTTNG_ERR_MAX_SIZE_INVALID;
+ goto error;
+ }
ret = record_ust_snapshot(usess, &tmp_output, session,
- wait, max_stream_size);
+ wait, nb_packets_per_stream);
if (ret != LTTNG_OK) {
goto error;
}
rcu_read_lock();
cds_lfht_for_each_entry(session->snapshot.output_ht->ht,
&iter.iter, sout, node.node) {
+ int64_t nb_packets_per_stream;
+
/*
* Make a local copy of the output and assign the possible
* temporary value given by the caller.
memset(&tmp_output, 0, sizeof(tmp_output));
memcpy(&tmp_output, sout, sizeof(tmp_output));
- /* Use temporary max size. */
if (output->max_size != (uint64_t) -1ULL) {
tmp_output.max_size = output->max_size;
}
- if (tmp_output.max_size != 0 &&
- tmp_output.max_size < session_max_size) {
- rcu_read_unlock();
+ nb_packets_per_stream = get_session_nb_packets_per_stream(session,
+ tmp_output.max_size);
+ if (nb_packets_per_stream < 0) {
ret = LTTNG_ERR_MAX_SIZE_INVALID;
+ rcu_read_unlock();
goto error;
}
tmp_output.nb_snapshot = session->snapshot.nb_snapshot;
ret = record_ust_snapshot(usess, &tmp_output, session,
- wait, max_stream_size);
+ wait, nb_packets_per_stream);
if (ret != LTTNG_OK) {
rcu_read_unlock();
goto error;
*/
int consumer_snapshot_channel(struct consumer_socket *socket, uint64_t key,
struct snapshot_output *output, int metadata, uid_t uid, gid_t gid,
- const char *session_path, int wait, int max_stream_size)
+ const char *session_path, int wait, uint64_t nb_packets_per_stream)
{
int ret;
struct lttcomm_consumer_msg msg;
memset(&msg, 0, sizeof(msg));
msg.cmd_type = LTTNG_CONSUMER_SNAPSHOT_CHANNEL;
msg.u.snapshot_channel.key = key;
- msg.u.snapshot_channel.max_stream_size = max_stream_size;
+ msg.u.snapshot_channel.nb_packets_per_stream = nb_packets_per_stream;
msg.u.snapshot_channel.metadata = metadata;
if (output->consumer->type == CONSUMER_DST_NET) {
/* Snapshot command. */
int consumer_snapshot_channel(struct consumer_socket *socket, uint64_t key,
struct snapshot_output *output, int metadata, uid_t uid, gid_t gid,
- const char *session_path, int wait, int max_size_per_stream);
+ const char *session_path, int wait, uint64_t nb_packets_per_stream);
#endif /* _CONSUMER_H */
* Return 0 on success or else return a LTTNG_ERR code.
*/
int kernel_snapshot_record(struct ltt_kernel_session *ksess,
- struct snapshot_output *output, int wait, uint64_t max_size_per_stream)
+ struct snapshot_output *output, int wait,
+ uint64_t nb_packets_per_stream)
{
int err, ret, saved_metadata_fd;
struct consumer_socket *socket;
ret = consumer_snapshot_channel(socket, chan->fd, output, 0,
ksess->uid, ksess->gid,
DEFAULT_KERNEL_TRACE_DIR, wait,
- max_size_per_stream);
+ nb_packets_per_stream);
pthread_mutex_unlock(socket->lock);
if (ret < 0) {
ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
pthread_mutex_lock(socket->lock);
ret = consumer_snapshot_channel(socket, ksess->metadata->fd, output,
1, ksess->uid, ksess->gid,
- DEFAULT_KERNEL_TRACE_DIR, wait, max_size_per_stream);
+ DEFAULT_KERNEL_TRACE_DIR, wait, 0);
pthread_mutex_unlock(socket->lock);
if (ret < 0) {
ret = LTTNG_ERR_KERN_CONSUMER_FAIL;
void kernel_destroy_session(struct ltt_kernel_session *ksess);
void kernel_destroy_channel(struct ltt_kernel_channel *kchan);
int kernel_snapshot_record(struct ltt_kernel_session *ksess,
- struct snapshot_output *output, int wait, uint64_t max_stream_size);
+ struct snapshot_output *output, int wait,
+ uint64_t nb_packets_per_stream);
int kernel_syscall_mask(int chan_fd, char **syscall_mask, uint32_t *nr_bits);
int init_kernel_workarounds(void);
{
int ret = 0, i;
- assert(output);
-
memset(output, 0, sizeof(struct snapshot_output));
+ /*
+ * max_size of -1ULL means unset. Set to default (unlimited).
+ */
if (max_size == (uint64_t) -1ULL) {
max_size = 0;
}
assert(reg_chan);
reg_chan->consumer_key = ua_chan->key;
reg_chan->subbuf_size = ua_chan->attr.subbuf_size;
+ reg_chan->num_subbuf = ua_chan->attr.num_subbuf;
/* Create and add a channel registry to session. */
ret = ust_registry_channel_add(reg_sess->reg.ust,
* Return 0 on success or else a negative value.
*/
int ust_app_snapshot_record(struct ltt_ust_session *usess,
- struct snapshot_output *output, int wait, uint64_t max_stream_size)
+ struct snapshot_output *output, int wait,
+ uint64_t nb_packets_per_stream)
{
int ret = 0;
unsigned int snapshot_done = 0;
reg_chan, node.node) {
ret = consumer_snapshot_channel(socket, reg_chan->consumer_key,
output, 0, usess->uid, usess->gid, pathname, wait,
- max_stream_size);
+ nb_packets_per_stream);
if (ret < 0) {
goto error;
}
}
ret = consumer_snapshot_channel(socket,
reg->registry->reg.ust->metadata_key, output, 1,
- usess->uid, usess->gid, pathname, wait, max_stream_size);
+ usess->uid, usess->gid, pathname, wait, 0);
if (ret < 0) {
goto error;
}
ua_chan, node.node) {
ret = consumer_snapshot_channel(socket, ua_chan->key, output,
0, ua_sess->euid, ua_sess->egid, pathname, wait,
- max_stream_size);
+ nb_packets_per_stream);
if (ret < 0) {
goto error;
}
registry = get_session_registry(ua_sess);
assert(registry);
ret = consumer_snapshot_channel(socket, registry->metadata_key, output,
- 1, ua_sess->euid, ua_sess->egid, pathname, wait,
- max_stream_size);
+ 1, ua_sess->euid, ua_sess->egid, pathname, wait, 0);
if (ret < 0) {
goto error;
}
}
/*
- * Return the number of streams for a UST session.
+ * Return the size taken by one more packet per stream.
*/
-unsigned int ust_app_get_nb_stream(struct ltt_ust_session *usess)
+uint64_t ust_app_get_size_one_more_packet_per_stream(struct ltt_ust_session *usess,
+ uint64_t cur_nr_packets)
{
- unsigned int ret = 0;
+ uint64_t tot_size = 0;
struct ust_app *app;
struct lttng_ht_iter iter;
rcu_read_lock();
cds_lfht_for_each_entry(reg->registry->channels->ht, &iter.iter,
reg_chan, node.node) {
- ret += reg_chan->stream_count;
+ if (cur_nr_packets >= reg_chan->num_subbuf) {
+ /*
+ * Don't take channel into account if we
+ * already grab all its packets.
+ */
+ continue;
+ }
+ tot_size += reg_chan->subbuf_size * reg_chan->stream_count;
}
rcu_read_unlock();
}
cds_lfht_for_each_entry(ua_sess->channels->ht, &chan_iter.iter,
ua_chan, node.node) {
- ret += ua_chan->streams.count;
+ if (cur_nr_packets >= ua_chan->attr.num_subbuf) {
+ /*
+ * Don't take channel into account if we
+ * already grab all its packets.
+ */
+ continue;
+ }
+ tot_size += ua_chan->attr.subbuf_size * ua_chan->streams.count;
}
}
rcu_read_unlock();
break;
}
- return ret;
+ return tot_size;
}
struct consumer_socket *socket, int send_zero_data);
void ust_app_destroy(struct ust_app *app);
int ust_app_snapshot_record(struct ltt_ust_session *usess,
- struct snapshot_output *output, int wait, uint64_t max_stream_size);
-unsigned int ust_app_get_nb_stream(struct ltt_ust_session *usess);
+ struct snapshot_output *output, int wait,
+ uint64_t nb_packets_per_stream);
+uint64_t ust_app_get_size_one_more_packet_per_stream(struct ltt_ust_session *usess,
+ uint64_t cur_nr_packets);
struct ust_app *ust_app_find_by_sock(int sock);
static inline
ret = lttng_snapshot_record(current_session_name, output, 0);
if (ret < 0) {
if (ret == -LTTNG_ERR_MAX_SIZE_INVALID) {
- ERR("The minimum size of a snapshot is computed by multiplying "
- "the total amount of streams with the largest subbuffer "
- "in the session.");
+ ERR("Invalid snapshot size. Cannot fit at least one packet per stream.");
}
goto error;
}
({ \
LTTNG_BUILD_RUNTIME_BUG_ON((alignment) == 0 \
|| ((alignment) & ((alignment) - 1))); \
- (((align_drift) - (alignment)) & ((alignment) - 1); \
+ (((align_drift) - (alignment)) & ((alignment) - 1)); \
})
#endif /* _LTTNG_ALIGN_H */
#include "consumer.h"
#include "consumer-stream.h"
#include "consumer-testpoint.h"
+#include "align.h"
struct lttng_consumer_global_data consumer_data = {
.stream_count = 0,
return lttcomm_send_unix_sock(sock, &msg, sizeof(msg));
}
-/*
- * Using a maximum stream size with the produced and consumed position of a
- * stream, computes the new consumed position to be as close as possible to the
- * maximum possible stream size.
- *
- * If maximum stream size is lower than the possible buffer size (produced -
- * consumed), the consumed_pos given is returned untouched else the new value
- * is returned.
- */
-unsigned long consumer_get_consumed_maxsize(unsigned long consumed_pos,
- unsigned long produced_pos, uint64_t max_stream_size)
+unsigned long consumer_get_consume_start_pos(unsigned long consumed_pos,
+ unsigned long produced_pos, uint64_t nb_packets_per_stream,
+ uint64_t max_sb_size)
{
- if (max_stream_size && max_stream_size < (produced_pos - consumed_pos)) {
- /* Offset from the produced position to get the latest buffers. */
- return produced_pos - max_stream_size;
- }
+ unsigned long start_pos;
- return consumed_pos;
+ if (!nb_packets_per_stream) {
+ return consumed_pos; /* Grab everything */
+ }
+ start_pos = produced_pos - offset_align_floor(produced_pos, max_sb_size);
+ start_pos -= max_sb_size * nb_packets_per_stream;
+ if ((long) (start_pos - consumed_pos) < 0) {
+ return consumed_pos; /* Grab everything */
+ }
+ return start_pos;
}
void notify_thread_del_channel(struct lttng_consumer_local_data *ctx,
uint64_t key);
void consumer_destroy_relayd(struct consumer_relayd_sock_pair *relayd);
-unsigned long consumer_get_consumed_maxsize(unsigned long consumed_pos,
- unsigned long produced_pos, uint64_t max_stream_size);
+unsigned long consumer_get_consume_start_pos(unsigned long consumed_pos,
+ unsigned long produced_pos, uint64_t nb_packets_per_stream,
+ uint64_t max_sb_size);
int consumer_add_data_stream(struct lttng_consumer_stream *stream);
void consumer_del_stream_for_data(struct lttng_consumer_stream *stream);
int consumer_add_metadata_stream(struct lttng_consumer_stream *stream);
* Returns 0 on success, < 0 on error
*/
int lttng_kconsumer_snapshot_channel(uint64_t key, char *path,
- uint64_t relayd_id, uint64_t max_stream_size,
+ uint64_t relayd_id, uint64_t nb_packets_per_stream,
struct lttng_consumer_local_data *ctx)
{
int ret;
}
}
- /*
- * The original value is sent back if max stream size is larger than
- * the possible size of the snapshot. Also, we asume that the session
- * daemon should never send a maximum stream size that is lower than
- * subbuffer size.
- */
- consumed_pos = consumer_get_consumed_maxsize(consumed_pos,
- produced_pos, max_stream_size);
+ consumed_pos = consumer_get_consume_start_pos(consumed_pos,
+ produced_pos, nb_packets_per_stream,
+ stream->max_sb_size);
while (consumed_pos < produced_pos) {
ssize_t read_len;
ret = lttng_kconsumer_snapshot_channel(msg.u.snapshot_channel.key,
msg.u.snapshot_channel.pathname,
msg.u.snapshot_channel.relayd_id,
- msg.u.snapshot_channel.max_stream_size,
+ msg.u.snapshot_channel.nb_packets_per_stream,
ctx);
if (ret < 0) {
ERR("Snapshot channel failed");
uint32_t metadata; /* This a metadata snapshot. */
uint64_t relayd_id; /* Relayd id if apply. */
uint64_t key;
- uint64_t max_stream_size;
+ uint64_t nb_packets_per_stream;
} LTTNG_PACKED snapshot_channel;
struct {
uint64_t channel_key;
* Returns 0 on success, < 0 on error
*/
static int snapshot_channel(uint64_t key, char *path, uint64_t relayd_id,
- uint64_t max_stream_size, struct lttng_consumer_local_data *ctx)
+ uint64_t nb_packets_per_stream, struct lttng_consumer_local_data *ctx)
{
int ret;
unsigned use_relayd = 0;
/*
* The original value is sent back if max stream size is larger than
- * the possible size of the snapshot. Also, we asume that the session
+ * the possible size of the snapshot. Also, we assume that the session
* daemon should never send a maximum stream size that is lower than
* subbuffer size.
*/
- consumed_pos = consumer_get_consumed_maxsize(consumed_pos,
- produced_pos, max_stream_size);
+ consumed_pos = consumer_get_consume_start_pos(consumed_pos,
+ produced_pos, nb_packets_per_stream,
+ stream->max_sb_size);
while (consumed_pos < produced_pos) {
ssize_t read_len;
ret = snapshot_channel(msg.u.snapshot_channel.key,
msg.u.snapshot_channel.pathname,
msg.u.snapshot_channel.relayd_id,
- msg.u.snapshot_channel.max_stream_size,
+ msg.u.snapshot_channel.nb_packets_per_stream,
ctx);
if (ret < 0) {
ERR("Snapshot channel failed");
projects / lttng-tools.git / commitdiff
