[PATCH] Basic support for a cpu cycle eater job

[fio.git] / fio.c

diff --git a/fio.c b/fio.c
index c83e8921c591647a47557e8a3ee0334dc6a3c14d..445babd5dfad5a38389b42db50389d35b4dbce39 100644 (file)
--- a/fio.c
+++ b/fio.c
@@ -777,6 +777,31 @@ static void do_verify(struct thread_data *td)
        td_set_runstate(td, TD_RUNNING);
 }
 
+/*
+ * Not really an io thread, all it does is burn CPU cycles in the specified
+ * manner.
+ */
+static void do_cpuio(struct thread_data *td)
+{
+       struct timeval e;
+       int split = 100 / td->cpuload;
+       int i = 0;
+
+       while (!td->terminate) {
+               gettimeofday(&e, NULL);
+
+               if (runtime_exceeded(td, &e))
+                       break;
+
+               if (!(i % split))
+                       __usec_sleep(10000);
+               else
+                       usec_sleep(td, 10000);
+
+               i++;
+       }
+}
+
 /*
  * Main IO worker function. It retrieves io_u's to process and queues
  * and reaps them, checking for rate and errors along the way.
@@ -890,6 +915,8 @@ static int init_io(struct thread_data *td)
                return fio_sgio_init(td);
        else if (td->io_engine == FIO_SPLICEIO)
                return fio_spliceio_init(td);
+       else if (td->io_engine == FIO_CPUIO)
+               return fio_cpuio_init(td);
        else {
                log_err("bad io_engine %d\n", td->io_engine);
                return 1;
@@ -929,6 +956,9 @@ static int init_io_u(struct thread_data *td)
        int i, max_units;
        char *p;
 
+       if (td->io_engine == FIO_CPUIO)
+               return 0;
+
        if (td->io_engine & FIO_SYNCIO)
                max_units = 1;
        else
@@ -1199,6 +1229,9 @@ static int setup_file(struct thread_data *td)
        struct stat st;
        int flags = 0;
 
+       if (td->io_engine == FIO_CPUIO)
+               return 0;
+
        if (stat(td->file_name, &st) == -1) {
                if (errno != ENOENT) {
                        td_verror(td, errno);
@@ -1390,7 +1423,10 @@ static void *thread_main(void *data)
                clear_io_state(td);
                prune_io_piece_log(td);
 
-               do_io(td);
+               if (td->io_engine == FIO_CPUIO)
+                       do_cpuio(td);
+               else
+                       do_io(td);
 
                td->runtime[td->ddir] += mtime_since_now(&td->start);
                if (td_rw(td) && td->io_bytes[td->ddir ^ 1])
@@ -1694,14 +1730,17 @@ static void print_thread_status(void)
  */
 static void reap_threads(int *nr_running, int *t_rate, int *m_rate)
 {
-       int i;
+       int i, cputhreads;
 
        /*
         * reap exited threads (TD_EXITED -> TD_REAPED)
         */
-       for (i = 0; i < thread_number; i++) {
+       for (i = 0, cputhreads = 0; i < thread_number; i++) {
                struct thread_data *td = &threads[i];
 
+               if (td->io_engine == FIO_CPUIO)
+                       cputhreads++;
+
                if (td->runstate != TD_EXITED)
                        continue;
 
@@ -1719,6 +1758,9 @@ static void reap_threads(int *nr_running, int *t_rate, int *m_rate)
                (*m_rate) -= td->ratemin;
                (*t_rate) -= td->rate;
        }
+
+       if (*nr_running == cputhreads)
+               terminate_threads(TERMINATE_ALL);
 }
 
 static void fio_unpin_memory(void *pinned)