[PATCH] blktrace: improve sendfile support (requires kernel change)

diff --git a/blktrace.c b/blktrace.c
index 1520029c5c5431be5de4387a8b82f5f90eb2200b..aea862596e000788c78252dd60607e368ee0ac0d 100644 (file)
--- a/blktrace.c
+++ b/blktrace.c
@@ -180,6 +180,9 @@ struct thread_information {
        void *fd_buf;
        char fn[MAXPATHLEN + 64];
 
+       int pfd;
+       size_t *pfd_buf;
+
        FILE *ofile;
        char *ofile_buffer;
        off_t ofile_offset;
@@ -326,6 +329,21 @@ static int get_dropped_count(const char *buts_name)
        return atoi(tmp);
 }
 
+static size_t get_subbuf_padding(struct thread_information *tip,
+                                unsigned subbuf)
+{
+       size_t padding_size = buf_nr * sizeof(size_t);
+       size_t ret;
+
+       if (read(tip->pfd, tip->pfd_buf, padding_size) < 0) {
+               perror("tip pad read");
+               ret = -1;
+       } else
+               ret = tip->pfd_buf[subbuf];
+
+       return ret;
+}
+
 static int start_trace(struct device_information *dip)
 {
        struct blk_user_trace_setup buts;
@@ -538,22 +556,39 @@ static int mmap_subbuf(struct thread_information *tip, unsigned int maxlen)
 static int get_subbuf_sendfile(struct thread_information *tip,
                               unsigned int maxlen)
 {
-       struct tip_subbuf *ts = malloc(sizeof(*ts));
+       struct tip_subbuf *ts;
        struct stat sb;
-
-       ts->max_len = maxlen;
-       ts->buf = NULL;
+       unsigned int ready;
+       int err;
 
        if (fstat(tip->fd, &sb) < 0) {
                perror("trace stat");
                return 1;
        }
 
-       ts->len = sb.st_size - tip->ofile_offset;
-       ts->max_len = ts->len;
-       ts->offset = tip->ofile_offset;
-       tip->ofile_offset += ts->len;
-       return subbuf_fifo_queue(tip, ts);
+       ready = sb.st_size - tip->ofile_offset;
+       if (!ready)
+               return 0;
+
+       while (ready) {
+               ts = malloc(sizeof(*ts));
+
+               ts->max_len = maxlen;
+               ts->buf = NULL;
+
+               ts->len = buf_size;
+               ts->max_len = ts->len;
+               ts->offset = tip->ofile_offset;
+               tip->ofile_offset += ts->len;
+
+               err = subbuf_fifo_queue(tip, ts);
+               if (err)
+                       return err;
+
+               ready -= buf_size;
+       }
+
+       return 0;
 }
 
 /*
@@ -580,14 +615,19 @@ static void close_thread(struct thread_information *tip)
 {
        if (tip->fd != -1)
                close(tip->fd);
+       if (tip->pfd != -1)
+               close(tip->pfd);
        if (tip->ofile)
                fclose(tip->ofile);
        if (tip->ofile_buffer)
                free(tip->ofile_buffer);
        if (tip->fd_buf)
                free(tip->fd_buf);
+       if (tip->pfd_buf)
+               free(tip->pfd_buf);
 
        tip->fd = -1;
+       tip->pfd = -1;
        tip->ofile = NULL;
        tip->ofile_buffer = NULL;
        tip->fd_buf = NULL;
@@ -632,6 +672,21 @@ static void *thread_main(void *arg)
                exit_trace(1);
        }
 
+       if (net_mode == Net_client && net_sendfile) {
+               char tmp[MAXPATHLEN + 64];
+
+               snprintf(tmp, sizeof(tmp), "%s/block/%s/trace%d.padding",
+                        relay_path, tip->device->buts_name, tip->cpu);
+
+               tip->pfd = open(tmp, O_RDONLY);
+               if (tip->pfd < 0) {
+                       fprintf(stderr, "Couldn't open padding file %s\n", tmp);
+                       exit_trace(1);
+               }
+
+               tip->pfd_buf = malloc(buf_nr * sizeof(size_t));
+       }
+
        while (!is_done()) {
                if (tip->get_subbuf(tip, buf_size))
                        break;
@@ -705,9 +760,17 @@ static int flush_subbuf_net(struct thread_information *tip,
 static int flush_subbuf_sendfile(struct thread_information *tip,
                                 struct tip_subbuf *ts)
 {
-       if (net_send_header(tip, ts->len))
+       size_t padding;
+       unsigned subbuf;
+       unsigned len;
+       
+       subbuf = (ts->offset / buf_size) % buf_nr;
+       padding = get_subbuf_padding(tip, subbuf);
+       len = ts->len - padding;
+
+       if (net_send_header(tip, len))
                return 1;
-       if (sendfile(net_out_fd, tip->fd, &ts->offset, ts->len) < 0) {
+       if (sendfile(net_out_fd, tip->fd, &ts->offset, len) < 0) {
                perror("sendfile");
                return 1;
        }
@@ -981,6 +1044,8 @@ static int start_threads(struct device_information *dip)
                tip->cpu = j;
                tip->device = dip;
                tip->events_processed = 0;
+               tip->fd = -1;
+               tip->pfd = -1;
                memset(&tip->fifo, 0, sizeof(tip->fifo));
                tip->leftover_ts = NULL;