cmdprio: add mode to make the logic easier to reason about

[fio.git] / engines / cmdprio.c

diff --git a/engines/cmdprio.c b/engines/cmdprio.c
index d36b6264e07d1dfb735ee2efb3ef2b735b8021a2..8c52dabdf3e86d671f35b825ea9a0807f36cb413 100644 (file)
--- a/engines/cmdprio.c
+++ b/engines/cmdprio.c
@@ -70,20 +70,23 @@ int fio_cmdprio_bssplit_parse(struct thread_data *td, const char *input,
 static int fio_cmdprio_percentage(struct cmdprio *cmdprio, struct io_u *io_u)
 {
        enum fio_ddir ddir = io_u->ddir;
-       unsigned int p = cmdprio->percentage[ddir];
        int i;
 
-       /*
-        * If cmdprio_percentage option was specified, then use that
-        * percentage. Otherwise, use cmdprio_bssplit percentages depending
-        * on the IO size.
-        */
-       if (p)
-               return p;
-
-       for (i = 0; i < cmdprio->bssplit_nr[ddir]; i++) {
-               if (cmdprio->bssplit[ddir][i].bs == io_u->buflen)
-                       return cmdprio->bssplit[ddir][i].perc;
+       switch (cmdprio->mode) {
+       case CMDPRIO_MODE_PERC:
+               return cmdprio->percentage[ddir];
+       case CMDPRIO_MODE_BSSPLIT:
+               for (i = 0; i < cmdprio->bssplit_nr[ddir]; i++) {
+                       if (cmdprio->bssplit[ddir][i].bs == io_u->buflen)
+                               return cmdprio->bssplit[ddir][i].perc;
+               }
+               break;
+       default:
+               /*
+                * An I/O engine should never call this function if cmdprio
+                * is not is use.
+                */
+               assert(0);
        }
 
        return 0;
@@ -104,10 +107,11 @@ bool fio_cmdprio_set_ioprio(struct thread_data *td, struct cmdprio *cmdprio,
                            struct io_u *io_u)
 {
        enum fio_ddir ddir = io_u->ddir;
-       unsigned int p = fio_cmdprio_percentage(cmdprio, io_u);
+       unsigned int p;
        unsigned int cmdprio_value =
                ioprio_value(cmdprio->class[ddir], cmdprio->level[ddir]);
 
+       p = fio_cmdprio_percentage(cmdprio, io_u);
        if (p && rand_between(&td->prio_state, 0, 99) < p) {
                io_u->ioprio = cmdprio_value;
                if (!td->ioprio || cmdprio_value < td->ioprio) {
@@ -134,8 +138,7 @@ bool fio_cmdprio_set_ioprio(struct thread_data *td, struct cmdprio *cmdprio,
        return false;
 }
 
-int fio_cmdprio_init(struct thread_data *td, struct cmdprio *cmdprio,
-                    bool *has_cmdprio)
+int fio_cmdprio_init(struct thread_data *td, struct cmdprio *cmdprio)
 {
        struct thread_options *to = &td->o;
        bool has_cmdprio_percentage = false;
@@ -169,7 +172,12 @@ int fio_cmdprio_init(struct thread_data *td, struct cmdprio *cmdprio,
                return 1;
        }
 
-       *has_cmdprio = has_cmdprio_percentage || has_cmdprio_bssplit;
+       if (has_cmdprio_bssplit)
+               cmdprio->mode = CMDPRIO_MODE_BSSPLIT;
+       else if (has_cmdprio_percentage)
+               cmdprio->mode = CMDPRIO_MODE_PERC;
+       else
+               cmdprio->mode = CMDPRIO_MODE_NONE;
 
        return 0;
 }