This patchs adds the wrappers to take a snapshot for a specific FD and to retreive the produced position. Also refactor the sync tracefile operation.
Signed-off-by: Julien Desfossez <[email protected]> --- include/lttng/lttng-kconsumerd.h | 18 ++++ liblttngkconsumerd/lttngkconsumerd.c | 142 +++++++++++++++++++--------------- 2 files changed, 98 insertions(+), 62 deletions(-) diff --git a/include/lttng/lttng-kconsumerd.h b/include/lttng/lttng-kconsumerd.h index 8d16d56..7e195ab 100644 --- a/include/lttng/lttng-kconsumerd.h +++ b/include/lttng/lttng-kconsumerd.h @@ -132,6 +132,24 @@ extern int lttng_kconsumerd_on_read_subbuffer_splice( struct lttng_kconsumerd_fd *kconsumerd_fd, unsigned long len); /* + * Take a snapshot for a specific fd + * + * Returns 0 on success, < 0 on error + */ +int lttng_kconsumerd_take_snapshot(struct lttng_kconsumerd_local_data *ctx, + struct lttng_kconsumerd_fd *kconsumerd_fd); + +/* + * Get the produced position + * + * Returns 0 on success, < 0 on error + */ +int lttng_kconsumerd_get_produced_snapshot( + struct lttng_kconsumerd_local_data *ctx, + struct lttng_kconsumerd_fd *kconsumerd_fd, + unsigned long *pos); + +/* * Send return code to session daemon. * * Returns the return code of sendmsg : the number of bytes transmitted or -1 diff --git a/liblttngkconsumerd/lttngkconsumerd.c b/liblttngkconsumerd/lttngkconsumerd.c index ba26026..d36da9b 100644 --- a/liblttngkconsumerd/lttngkconsumerd.c +++ b/liblttngkconsumerd/lttngkconsumerd.c @@ -361,6 +361,42 @@ void lttng_kconsumerd_set_command_sock_path( ctx->kconsumerd_command_sock_path = sock; } +static void lttng_kconsumerd_sync_trace_file( + struct lttng_kconsumerd_fd *kconsumerd_fd, off_t orig_offset) +{ + int outfd = kconsumerd_fd->out_fd; + /* + * This does a blocking write-and-wait on any page that belongs to the + * subbuffer prior to the one we just wrote. + * Don't care about error values, as these are just hints and ways to + * limit the amount of page cache used. + */ + if (orig_offset >= kconsumerd_fd->max_sb_size) { + sync_file_range(outfd, orig_offset - kconsumerd_fd->max_sb_size, + kconsumerd_fd->max_sb_size, + SYNC_FILE_RANGE_WAIT_BEFORE + | SYNC_FILE_RANGE_WRITE + | SYNC_FILE_RANGE_WAIT_AFTER); + /* + * Give hints to the kernel about how we access the file: + * POSIX_FADV_DONTNEED : we won't re-access data in a near future after + * we write it. + * + * We need to call fadvise again after the file grows because the + * kernel does not seem to apply fadvise to non-existing parts of the + * file. + * + * Call fadvise _after_ having waited for the page writeback to + * complete because the dirty page writeback semantic is not well + * defined. So it can be expected to lead to lower throughput in + * streaming. + */ + posix_fadvise(outfd, orig_offset - kconsumerd_fd->max_sb_size, + kconsumerd_fd->max_sb_size, POSIX_FADV_DONTNEED); + } +} + + /* * Mmap the ring buffer, read it and write the data to the tracefile. * @@ -371,7 +407,6 @@ int lttng_kconsumerd_on_read_subbuffer_mmap( struct lttng_kconsumerd_fd *kconsumerd_fd, unsigned long len) { unsigned long mmap_offset; - char *padding = NULL; long ret = 0; off_t orig_offset = kconsumerd_fd->out_fd_offset; int fd = kconsumerd_fd->consumerd_fd; @@ -400,42 +435,11 @@ int lttng_kconsumerd_on_read_subbuffer_mmap( kconsumerd_fd->out_fd_offset += ret; } - /* - * This does a blocking write-and-wait on any page that belongs to the - * subbuffer prior to the one we just wrote. - * Don't care about error values, as these are just hints and ways to - * limit the amount of page cache used. - */ - if (orig_offset >= kconsumerd_fd->max_sb_size) { - sync_file_range(outfd, orig_offset - kconsumerd_fd->max_sb_size, - kconsumerd_fd->max_sb_size, - SYNC_FILE_RANGE_WAIT_BEFORE - | SYNC_FILE_RANGE_WRITE - | SYNC_FILE_RANGE_WAIT_AFTER); + lttng_kconsumerd_sync_trace_file(kconsumerd_fd, orig_offset); - /* - * Give hints to the kernel about how we access the file: - * POSIX_FADV_DONTNEED : we won't re-access data in a near future after - * we write it. - * - * We need to call fadvise again after the file grows because the - * kernel does not seem to apply fadvise to non-existing parts of the - * file. - * - * Call fadvise _after_ having waited for the page writeback to - * complete because the dirty page writeback semantic is not well - * defined. So it can be expected to lead to lower throughput in - * streaming. - */ - posix_fadvise(outfd, orig_offset - kconsumerd_fd->max_sb_size, - kconsumerd_fd->max_sb_size, POSIX_FADV_DONTNEED); - } goto end; end: - if (padding != NULL) { - free(padding); - } return ret; } @@ -482,36 +486,8 @@ int lttng_kconsumerd_on_read_subbuffer_splice( SYNC_FILE_RANGE_WRITE); kconsumerd_fd->out_fd_offset += ret; } + lttng_kconsumerd_sync_trace_file(kconsumerd_fd, orig_offset); - /* - * This does a blocking write-and-wait on any page that belongs to the - * subbuffer prior to the one we just wrote. - * Don't care about error values, as these are just hints and ways to - * limit the amount of page cache used. - */ - if (orig_offset >= kconsumerd_fd->max_sb_size) { - sync_file_range(outfd, orig_offset - kconsumerd_fd->max_sb_size, - kconsumerd_fd->max_sb_size, - SYNC_FILE_RANGE_WAIT_BEFORE - | SYNC_FILE_RANGE_WRITE - | SYNC_FILE_RANGE_WAIT_AFTER); - /* - * Give hints to the kernel about how we access the file: - * POSIX_FADV_DONTNEED : we won't re-access data in a near future after - * we write it. - * - * We need to call fadvise again after the file grows because the - * kernel does not seem to apply fadvise to non-existing parts of the - * file. - * - * Call fadvise _after_ having waited for the page writeback to - * complete because the dirty page writeback semantic is not well - * defined. So it can be expected to lead to lower throughput in - * streaming. - */ - posix_fadvise(outfd, orig_offset - kconsumerd_fd->max_sb_size, - kconsumerd_fd->max_sb_size, POSIX_FADV_DONTNEED); - } goto end; splice_error: @@ -536,6 +512,48 @@ end: } /* + * Take a snapshot for a specific fd + * + * Returns 0 on success, < 0 on error + */ +int lttng_kconsumerd_take_snapshot(struct lttng_kconsumerd_local_data *ctx, + struct lttng_kconsumerd_fd *kconsumerd_fd) +{ + int ret = 0; + int infd = kconsumerd_fd->consumerd_fd; + + ret = kernctl_snapshot(infd); + if (ret != 0) { + ret = errno; + perror("Getting sub-buffer snapshot."); + } + + return ret; +} + +/* + * Get the produced position + * + * Returns 0 on success, < 0 on error + */ +int lttng_kconsumerd_get_produced_snapshot( + struct lttng_kconsumerd_local_data *ctx, + struct lttng_kconsumerd_fd *kconsumerd_fd, + unsigned long *pos) +{ + int ret; + int infd = kconsumerd_fd->consumerd_fd; + + ret = kernctl_snapshot_get_produced(infd, pos); + if (ret != 0) { + ret = errno; + perror("kernctl_snapshot_get_produced"); + } + + return ret; +} + +/* * Poll on the should_quit pipe and the command socket return -1 on error and * should exit, 0 if data is available on the command socket */ -- 1.7.4.1 _______________________________________________ ltt-dev mailing list [email protected] http://lists.casi.polymtl.ca/cgi-bin/mailman/listinfo/ltt-dev
