netem: use fixed rather than floating point for scaling

Don't need to do floating point math to compute scaled random.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/tc/q_netem.c b/tc/q_netem.c
index cdaddce9d1b76d5cb6f719fd27cb336ea1bfab95..b97c351e07736eada5cae17ba3c9c0e48b3b15f1 100644 (file)
--- a/tc/q_netem.c
+++ b/tc/q_netem.c
@@ -17,6 +17,7 @@
 #include <unistd.h>
 #include <syslog.h>
 #include <fcntl.h>
+#include <stdint.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <arpa/inet.h>
@@ -53,15 +54,12 @@ static void explain1(const char *arg)
  */
 #define MAX_DIST       (16*1024)
 
-static const double max_percent_value = 0xffffffff;
-
 /* scaled value used to percent of maximum. */
 static void set_percent(__u32 *percent, double per)
 {
-       *percent = (unsigned int) rint(per * max_percent_value);
+       *percent = rint(per * UINT32_MAX);
 }
 
-
 /* Parse either a fraction '.3' or percent '30%
  * return: 0 = ok, -1 = error, 1 = out of range
  */
@@ -89,7 +87,7 @@ static int get_percent(__u32 *percent, const char *str)
 
 static void print_percent(char *buf, int len, __u32 per)
 {
-       snprintf(buf, len, "%g%%", 100. * (double) per / max_percent_value);
+       snprintf(buf, len, "%g%%", (100. * per) / UINT32_MAX);
 }
 
 static char *sprint_percent(__u32 per, char *buf)
@@ -323,7 +321,7 @@ static int netem_parse_opt(struct qdisc_util *qu, int argc, char **argv,
                                /* netem option is "1-h" but kernel
                                 * expects "h".
                                 */
-                               gemodel.h = max_percent_value - gemodel.h;
+                               gemodel.h = UINT32_MAX - gemodel.h;
 
                                if (!NEXT_IS_NUMBER())
                                        continue;
@@ -630,7 +628,7 @@ static int netem_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
                fprintf(f, " loss gemodel p %s",
                        sprint_percent(gemodel->p, b1));
                fprintf(f, " r %s", sprint_percent(gemodel->r, b1));
-               fprintf(f, " 1-h %s", sprint_percent(max_percent_value -
+               fprintf(f, " 1-h %s", sprint_percent(UINT32_MAX -
                                                     gemodel->h, b1));
                fprintf(f, " 1-k %s", sprint_percent(gemodel->k1, b1));
        }