[PATCH] Various little fixes and lots of commenting
diff --git a/fio.c b/fio.c
index 5bced24..412f002 100644
--- a/fio.c
+++ b/fio.c
@@ -103,6 +103,10 @@
}
}
+/*
+ * The ->file_map[] contains a map of blocks we have or have not done io
+ * to yet. Used to make sure we cover the entire range in a fair fashion.
+ */
static int random_map_free(struct thread_data *td, unsigned long long block)
{
unsigned int idx = RAND_MAP_IDX(td, block);
@@ -111,6 +115,9 @@
return (td->file_map[idx] & (1UL << bit)) == 0;
}
+/*
+ * Return the next free block in the map.
+ */
static int get_next_free_block(struct thread_data *td, unsigned long long *b)
{
int i;
@@ -130,6 +137,9 @@
return 1;
}
+/*
+ * Mark a given offset as used in the map.
+ */
static void mark_random_map(struct thread_data *td, struct io_u *io_u)
{
unsigned long long block = io_u->offset / (unsigned long long) td->min_bs;
@@ -155,6 +165,11 @@
io_u->buflen = blocks * td->min_bs;
}
+/*
+ * For random io, generate a random new block and see if it's used. Repeat
+ * until we find a free one. For sequential io, just return the end of
+ * the last io issued.
+ */
static int get_next_offset(struct thread_data *td, unsigned long long *offset)
{
unsigned long long b, rb;
@@ -204,6 +219,9 @@
return buflen;
}
+/*
+ * Check if we are above the minimum rate given.
+ */
static int check_min_rate(struct thread_data *td, struct timeval *now)
{
unsigned long spent;
@@ -352,6 +370,11 @@
memcpy(hdr->md5_digest, md5_ctx.hash, sizeof(md5_ctx.hash));
}
+/*
+ * Return the data direction for the next io_u. If the job is a
+ * mixed read/write workload, check the rwmix cycle and switch if
+ * necessary.
+ */
static int get_rw_ddir(struct thread_data *td)
{
if (td_rw(td)) {
@@ -472,6 +495,10 @@
return io_u;
}
+/*
+ * Return an io_u to be processed. Gets a buflen and offset, sets direction,
+ * etc. The returned io_u is fully ready to be prepped and submitted.
+ */
static struct io_u *get_io_u(struct thread_data *td)
{
struct io_u *io_u;
@@ -608,6 +635,10 @@
}
}
+/*
+ * When job exits, we can cancel the in-flight IO if we are using async
+ * io. Attempt to do so.
+ */
static void cleanup_pending_aio(struct thread_data *td)
{
struct timespec ts = { .tv_sec = 0, .tv_nsec = 0};
@@ -661,6 +692,10 @@
return ret;
}
+/*
+ * The main verify engine. Runs over the writes we previusly submitted,
+ * reads the blocks back in, and checks the crc/md5 of the data.
+ */
static void do_verify(struct thread_data *td)
{
struct timeval t;
@@ -742,7 +777,7 @@
}
/*
- * Main IO worker functions. It retrieves io_u's to process and queues
+ * Main IO worker function. It retrieves io_u's to process and queues
* and reaps them, checking for rate and errors along the way.
*/
static void do_io(struct thread_data *td)
@@ -1281,6 +1316,10 @@
memset(td->file_map, 0, td->num_maps * sizeof(long));
}
+/*
+ * Entry point for the thread based jobs. The process based jobs end up
+ * here as well, after a little setup.
+ */
static void *thread_main(void *data)
{
struct thread_data *td = data;
@@ -1403,6 +1442,10 @@
}
+/*
+ * We cannot pass the td data into a forked process, so attach the td and
+ * pass it to the thread worker.
+ */
static void *fork_main(int shmid, int offset)
{
struct thread_data *td;
@@ -1420,6 +1463,9 @@
return NULL;
}
+/*
+ * Sets the status of the 'td' in the printed status map.
+ */
static void check_str_update(struct thread_data *td)
{
char c = run_str[td->thread_number - 1];
@@ -1471,6 +1517,9 @@
run_str[td->thread_number - 1] = c;
}
+/*
+ * Convert seconds to a printable string.
+ */
static void eta_to_str(char *str, int eta_sec)
{
unsigned int d, h, m, s;
@@ -1499,6 +1548,9 @@
str += sprintf(str, "%02ds", s);
}
+/*
+ * Best effort calculation of the estimated pending runtime of a job.
+ */
static int thread_eta(struct thread_data *td, unsigned long elapsed)
{
unsigned long long bytes_total, bytes_done;
@@ -1564,6 +1616,10 @@
return eta_sec;
}
+/*
+ * Print status of the jobs we know about. This includes rate estimates,
+ * ETA, thread state, etc.
+ */
static void print_thread_status(void)
{
unsigned long elapsed = time_since_now(&genesis);
@@ -1632,6 +1688,9 @@
free(eta_secs);
}
+/*
+ * Run over the job map and reap the threads that have exited, if any.
+ */
static void reap_threads(int *nr_running, int *t_rate, int *m_rate)
{
int i;
@@ -1703,6 +1762,9 @@
return ptr;
}
+/*
+ * Main function for kicking off and reaping jobs, as needed.
+ */
static void run_threads(void)
{
struct thread_data *td;