[dpdk-dev] [PATCH v4 9/9] examples/vm_power: make branch ratio configurable

[David Hunt <david.hunt@intel.com>]

For different workloads and poll loops, the theshold
may be different for when you want to scale up and down.

This patch allows changing of the default branch ratio
by using the -b command line argument (or --branch-ratio=)

Signed-off-by: David Hunt <david.hunt@intel.com>
Acked-by: Radu Nicolau <radu.nicolau@intel.com>
---
 examples/vm_power_manager/main.c            | 16 +++++++++++++++-
 examples/vm_power_manager/oob_monitor_x86.c |  3 +--
 examples/vm_power_manager/power_manager.c   |  1 +
 examples/vm_power_manager/power_manager.h   |  3 +++
 4 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/examples/vm_power_manager/main.c b/examples/vm_power_manager/main.c
index f9990f153..58c5fa45c 100644
--- a/examples/vm_power_manager/main.c
+++ b/examples/vm_power_manager/main.c
@@ -141,17 +141,19 @@ parse_args(int argc, char **argv)
 	int option_index;
 	char *prgname = argv[0];
 	struct core_info *ci;
+	float branch_ratio;
 	static struct option lgopts[] = {
 		{ "mac-updating", no_argument, 0, 1},
 		{ "no-mac-updating", no_argument, 0, 0},
 		{ "core-list", optional_argument, 0, 'l'},
 		{ "port-list", optional_argument, 0, 'p'},
+		{ "branch-ratio", optional_argument, 0, 'b'},
 		{NULL, 0, 0, 0}
 	};
 	argvopt = argv;
 	ci = get_core_info();
 
-	while ((opt = getopt_long(argc, argvopt, "l:p:q:T:",
+	while ((opt = getopt_long(argc, argvopt, "l:p:q:T:b:",
 				  lgopts, &option_index)) != EOF) {
 
 		switch (opt) {
@@ -184,6 +186,18 @@ parse_args(int argc, char **argv)
 			}
 			free(oob_enable);
 			break;
+		case 'b':
+			branch_ratio = 0.0;
+			if (strlen(optarg))
+				branch_ratio = atof(optarg);
+			if (branch_ratio <= 0.0) {
+				printf("invalid branch ratio specified\n");
+				return -1;
+			}
+			ci->branch_ratio_threshold = branch_ratio;
+			printf("***Setting branch ratio to %f\n",
+					branch_ratio);
+			break;
 		/* long options */
 		case 0:
 			break;
diff --git a/examples/vm_power_manager/oob_monitor_x86.c b/examples/vm_power_manager/oob_monitor_x86.c
index 62d503ca5..589c604e5 100644
--- a/examples/vm_power_manager/oob_monitor_x86.c
+++ b/examples/vm_power_manager/oob_monitor_x86.c
@@ -22,7 +22,6 @@ void branch_monitor_exit(void)
 /* Number of microseconds between each poll */
 #define INTERVAL 100
 #define PRINT_LOOP_COUNT (1000000/INTERVAL)
-#define RATIO_THRESHOLD 0.03
 #define IA32_PERFEVTSEL0 0x186
 #define IA32_PERFEVTSEL1 0x187
 #define IA32_PERFCTR0 0xc1
@@ -89,7 +88,7 @@ apply_policy(int core)
 
 	ratio = (float)miss_diff * (float)100 / (float)hits_diff;
 
-	if (ratio < RATIO_THRESHOLD)
+	if (ratio < ci->branch_ratio_threshold)
 		power_manager_scale_core_min(core);
 	else
 		power_manager_scale_core_max(core);
diff --git a/examples/vm_power_manager/power_manager.c b/examples/vm_power_manager/power_manager.c
index 4bdde23da..b7769c3c3 100644
--- a/examples/vm_power_manager/power_manager.c
+++ b/examples/vm_power_manager/power_manager.c
@@ -74,6 +74,7 @@ core_info_init(void)
 	ci = get_core_info();
 
 	ci->core_count = get_nprocs_conf();
+	ci->branch_ratio_threshold = BRANCH_RATIO_THRESHOLD;
 	ci->cd = malloc(ci->core_count * sizeof(struct core_details));
 	if (!ci->cd) {
 		RTE_LOG(ERR, POWER_MANAGER, "Failed to allocate memory for core info.");
diff --git a/examples/vm_power_manager/power_manager.h b/examples/vm_power_manager/power_manager.h
index 45385de37..605b3c8f6 100644
--- a/examples/vm_power_manager/power_manager.h
+++ b/examples/vm_power_manager/power_manager.h
@@ -19,8 +19,11 @@ struct core_details {
 struct core_info {
 	uint16_t core_count;
 	struct core_details *cd;
+	float branch_ratio_threshold;
 };
 
+#define BRANCH_RATIO_THRESHOLD 0.1
+
 struct core_info *
 get_core_info(void);
 
-- 
2.17.1