xl: Implement sched-credit schedule parameter command-line interface

Add features to the sched-credit interface to allow querying and
displaying scheduler parameters.

Signed-off-by: George Dunlap <george.dunlap@eu.citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Committed-by: Ian Jackson <ian.jackson@eu.citrix.com>

3 files changed, 168 insertions, 17 deletions

diff --git a/docs/man/xl.pod.1 b/docs/man/xl.pod.1
index 7802a027c8..2ab8418a00 100644
--- a/docs/man/xl.pod.1
+++ b/docs/man/xl.pod.1
@@ -714,6 +714,53 @@ no upper cap.
 
 Restrict output to domains in the specified cpupool.
 
+=item B<-s>, B<--schedparam>
+
+Specify to list or set pool-wide scheduler parameters.
+
+=item B<-t TSLICE>, B<--tslice_ms=TSLICE>
+
+Timeslice tells the scheduler how long to allow VMs to run before
+pre-empting.  The default is 30ms.  Valid ranges are 1ms to 1000ms.
+The length of the timeslice (in ms) must be higher than the length of
+the ratelimit (see below).
+
+=item B<-r RLIMIT>, B<--ratelimit_us=RLIMIT>
+
+Ratelimit attempts to limit the number of schedules per second.  It
+sets a minimum amount of time (in microseconds) a VM must run before
+we will allow a higher-prioirty VM to pre-empt it.  The default value
+is 1000 microseconds (1ms).  Valid range is 100 to 500000 (500ms).
+The ratelimit length must be lower than the timeslice length.
+
+=back
+
+B<COMBINATION>
+
+The following is the effect of combining the above options:
+
+=over 4
+
+=item B<E<lt>nothingE<gt>>             : List all domain params and sched params from all pools
+
+=item B<-d [domid]>            : List domain params for domain [domid]
+
+=item B<-d [domid] [params]>   : Set domain params for domain [domid]
+
+=item B<-p [pool]>             : list all domains and sched params for [pool]
+
+=item B<-s>                    : List sched params for poolid 0
+
+=item B<-s [params]>           : Set sched params for poolid 0
+
+=item B<-p [pool] -s>          : List sched params for [pool]
+
+=item B<-p [pool] -s [params]> : Set sched params for [pool]
+
+=item B<-p [pool] -d>...       : Illegal
+
+=item
+
 =back
 
 =item B<sched-credit2> [I<OPTIONS>]
diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
index 30972879db..1d59b89b4d 100644
--- a/tools/libxl/xl_cmdimpl.c
+++ b/tools/libxl/xl_cmdimpl.c
@@ -3906,8 +3906,7 @@ int main_sharing(int argc, char **argv)
     return 0;
 }
 
-static int sched_credit_domain_get(
-    int domid, libxl_sched_credit_domain *scinfo)
+static int sched_credit_domain_get(int domid, libxl_sched_credit_domain *scinfo)
 {
     int rc;
 
@@ -3918,8 +3917,7 @@ static int sched_credit_domain_get(
     return rc;
 }
 
-static int sched_credit_domain_set(
-    int domid, libxl_sched_credit_domain *scinfo)
+static int sched_credit_domain_set(int domid, libxl_sched_credit_domain *scinfo)
 {
     int rc;
 
@@ -3931,8 +3929,29 @@ static int sched_credit_domain_set(
     return rc;
 }
 
-static int sched_credit_domain_output(
-    int domid)
+static int sched_credit_params_set(int poolid, libxl_sched_credit_params *scinfo)
+{
+    int rc;
+
+    rc = libxl_sched_credit_params_set(ctx, poolid, scinfo);
+    if (rc)
+        fprintf(stderr, "libxl_sched_credit_params_set failed.\n");
+
+    return rc;
+}
+
+static int sched_credit_params_get(int poolid, libxl_sched_credit_params *scinfo)
+{
+    int rc;
+
+    rc = libxl_sched_credit_params_get(ctx, poolid, scinfo);
+    if (rc)
+        fprintf(stderr, "libxl_sched_credit_params_get failed.\n");
+
+    return rc;
+}
+
+static int sched_credit_domain_output(int domid)
 {
     char *domname;
     libxl_sched_credit_domain scinfo;
@@ -3956,6 +3975,27 @@ static int sched_credit_domain_output(
     return 0;
 }
 
+static int sched_credit_pool_output(uint32_t poolid)
+{
+    libxl_sched_credit_params scparam;
+    char *poolname;
+    int rc;
+
+    poolname = libxl_cpupoolid_to_name(ctx, poolid);
+    rc = sched_credit_params_get(poolid, &scparam);
+    if (rc) {
+        printf("Cpupool %s: [sched params unavailable]\n",
+               poolname);
+    } else {
+        printf("Cpupool %s: tslice=%dms ratelimit=%dus\n",
+               poolname,
+               scparam.tslice_ms,
+               scparam.ratelimit_us);
+    }
+    free(poolname);
+    return 0;
+}
+
 static int sched_credit2_domain_get(
     int domid, libxl_sched_credit2_domain *scinfo)
 {
@@ -4119,25 +4159,41 @@ static int sched_domain_output(libxl_scheduler sched, int (*output)(int),
     return 0;
 }
 
+/* 
+ * <nothing>             : List all domain params and sched params from all pools
+ * -d [domid]            : List domain params for domain
+ * -d [domid] [params]   : Set domain params for domain
+ * -p [pool]             : list all domains and sched params for pool
+ * -s                    : List sched params for poolid 0
+ * -s [params]           : Set sched params for poolid 0
+ * -p [pool] -s          : List sched params for pool
+ * -p [pool] -s [params] : Set sched params for pool
+ * -p [pool] -d...       : Illegal
+ */
 int main_sched_credit(int argc, char **argv)
 {
     libxl_sched_credit_domain scinfo;
     const char *dom = NULL;
     const char *cpupool = NULL;
     int weight = 256, cap = 0, opt_w = 0, opt_c = 0;
+    int opt_s = 0;
+    int tslice = 0, opt_t = 0, ratelimit = 0, opt_r = 0;
     int opt, rc;
     int option_index = 0;
     static struct option long_options[] = {
         {"domain", 1, 0, 'd'},
         {"weight", 1, 0, 'w'},
         {"cap", 1, 0, 'c'},
+        {"schedparam", 0, 0, 's'},
+        {"tslice_ms", 1, 0, 't'},
+        {"ratelimit_us", 1, 0, 'r'},
         {"cpupool", 1, 0, 'p'},
         {"help", 0, 0, 'h'},
         {0, 0, 0, 0}
     };
 
     while (1) {
-        opt = getopt_long(argc, argv, "d:w:c:p:h", long_options,
+        opt = getopt_long(argc, argv, "d:w:c:p:t:r:hs", long_options,
                           &option_index);
         if (opt == -1)
             break;
@@ -4155,6 +4211,17 @@ int main_sched_credit(int argc, char **argv)
             cap = strtol(optarg, NULL, 10);
             opt_c = 1;
             break;
+        case 't':
+            tslice = strtol(optarg, NULL, 10);
+            opt_t = 1;
+            break;
+        case 'r':
+            ratelimit = strtol(optarg, NULL, 10);
+            opt_r = 1;
+            break;
+        case 's':
+            opt_s = 1;
+            break;
         case 'p':
             cpupool = optarg;
             break;
@@ -4164,20 +4231,54 @@ int main_sched_credit(int argc, char **argv)
         }
     }
 
-    if (cpupool && (dom || opt_w || opt_c)) {
-        fprintf(stderr, "Specifying a cpupool is not allowed with other "
-                "options.\n");
+    if ((cpupool || opt_s) && (dom || opt_w || opt_c)) {
+        fprintf(stderr, "Specifying a cpupool or schedparam is not "
+                "allowed with domain options.\n");
         return 1;
     }
     if (!dom && (opt_w || opt_c)) {
         fprintf(stderr, "Must specify a domain.\n");
         return 1;
     }
+    if (!opt_s && (opt_t || opt_r)) {
+        fprintf(stderr, "Must specify schedparam to set schedule "
+                "parameter values.\n");
+        return 1;
+    }
 
-    if (!dom) { /* list all domain's credit scheduler info */
+    if (opt_s) {
+        libxl_sched_credit_params  scparam;
+        uint32_t poolid = 0;
+
+        if (cpupool) {
+            if (cpupool_qualifier_to_cpupoolid(cpupool, &poolid, NULL) ||
+                !libxl_cpupoolid_to_name(ctx, poolid)) {
+                fprintf(stderr, "unknown cpupool \'%s\'\n", cpupool);
+                return -ERROR_FAIL;
+            }
+        }
+
+        if (!opt_t && !opt_r) { /* Output scheduling parameters */
+            return -sched_credit_pool_output(poolid);
+        } else { /* Set scheduling parameters*/
+            rc = sched_credit_params_get(poolid, &scparam);
+            if (rc)
+                return -rc;
+
+            if (opt_t)
+                scparam.tslice_ms = tslice;
+
+            if (opt_r)
+                scparam.ratelimit_us = ratelimit;
+
+            rc = sched_credit_params_set(poolid, &scparam);
+            if (rc)
+                return -rc;
+        }
+    } else if (!dom) { /* list all domain's credit scheduler info */
         return -sched_domain_output(LIBXL_SCHEDULER_CREDIT,
                                     sched_credit_domain_output,
-                                    sched_default_pool_output,
+                                    sched_credit_pool_output,
                                     cpupool);
     } else {
         find_domain(dom);
diff --git a/tools/libxl/xl_cmdtable.c b/tools/libxl/xl_cmdtable.c
index 888180954a..352ea87951 100644
--- a/tools/libxl/xl_cmdtable.c
+++ b/tools/libxl/xl_cmdtable.c
@@ -204,11 +204,14 @@ struct cmd_spec cmd_table[] = {
     { "sched-credit",
       &main_sched_credit, 0,
       "Get/set credit scheduler parameters",
-      "[-d <Domain> [-w[=WEIGHT]|-c[=CAP]]] [-p CPUPOOL]",
-      "-d DOMAIN, --domain=DOMAIN     Domain to modify\n"
-      "-w WEIGHT, --weight=WEIGHT     Weight (int)\n"
-      "-c CAP, --cap=CAP              Cap (int)\n"
-      "-p CPUPOOL, --cpupool=CPUPOOL  Restrict output to CPUPOOL"
+      "[-d <Domain> [-w[=WEIGHT]|-c[=CAP]]] [-s [-t TSLICE] [-r RATELIMIT]] [-p CPUPOOL]",
+      "-d DOMAIN, --domain=DOMAIN        Domain to modify\n"
+      "-w WEIGHT, --weight=WEIGHT        Weight (int)\n"
+      "-c CAP, --cap=CAP                 Cap (int)\n"
+      "-s         --schedparam           Query / modify scheduler parameters\n"
+      "-t TSLICE, --tslice_ms=TSLICE     Set the timeslice, in milliseconds\n"
+      "-r RLIMIT, --ratelimit_us=RLIMIT  Set the scheduling rate limit, in microseconds\n"
+      "-p CPUPOOL, --cpupool=CPUPOOL     Restrict output to CPUPOOL"
     },
     { "sched-credit2",
       &main_sched_credit2, 0,