Allow ranges of CPUs in cpus_allowed option

For a larger number of CPUs, it's a bit of a bother having to set
each one individually. Plus, you typically want to bind to a range of
CPUs, to keep the job core local (or whatever your preference). So extend
cpus_allowed to take ranges of CPU numbers as well. Now you can do:

cpus_allowed=0-7

and have your job confined to CPUs 0 through 7.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/HOWTO b/HOWTO
index 5a55c1a21b574a3adba1aa52f4f0fee6f42458c7..7bd71a9a961c64c69ba8fec686fa1cb262c45a8c 100644 (file)
--- a/HOWTO
+++ b/HOWTO
@@ -590,7 +590,9 @@ cpumask=int Set the CPU affinity of this job. The parameter given is a
 
 cpus_allowed=str Controls the same options as cpumask, but it allows a text
                setting of the permitted CPUs instead. So to use CPUs 1 and
-               5, you would specify cpus_allowed=1,5.
+               5, you would specify cpus_allowed=1,5. This options also
+               allows a range of CPUs. Say you wanted a binding to CPUs
+               1, 5, and 8-15, you would set cpus_allowed=1,5,8-15.
 
 startdelay=time        Start this job the specified number of seconds after fio
                has started. Only useful if the job file contains several

diff --git a/options.c b/options.c
index b890420f4e4e06c75f0c8f0c787f9c4597fd844f..1953e3d604216c53a1a12c86493d73e18cb75fb1 100644 (file)
--- a/options.c
+++ b/options.c
@@ -249,9 +249,12 @@ static int str_cpumask_cb(void *data, unsigned int *val)
 
        CPU_ZERO(&td->o.cpumask);
 
-       for (i = 0; i < sizeof(int) * 8; i++)
-               if ((1 << i) & *val)
+       for (i = 0; i < sizeof(int) * 8; i++) {
+               if ((1 << i) & *val) {
+                       dprint(FD_PARSE, "set cpu allowed %d\n", i);
                        CPU_SET(*val, &td->o.cpumask);
+               }
+       }
 
        td->o.cpumask_set = 1;
        return 0;
@@ -270,9 +273,29 @@ static int str_cpus_allowed_cb(void *data, const char *input)
        strip_blank_end(str);
 
        while ((cpu = strsep(&str, ",")) != NULL) {
+               char *str2, *cpu2;
+               int icpu, icpu2;
+
                if (!strlen(cpu))
                        break;
-               CPU_SET(atoi(cpu), &td->o.cpumask);
+
+               str2 = cpu;
+               icpu2 = -1;
+               while ((cpu2 = strsep(&str2, "-")) != NULL) {
+                       if (!strlen(cpu2))
+                               break;
+
+                       icpu2 = atoi(cpu2);
+               }
+
+               icpu = atoi(cpu);
+               if (icpu2 == -1)
+                       icpu2 = icpu;
+               while (icpu <= icpu2) {
+                       dprint(FD_PARSE, "set cpu allowed %d\n", icpu);
+                       CPU_SET(atoi(cpu), &td->o.cpumask);
+                       icpu++;
+               }
        }
 
        free(p);