red: harddrop support and cleanups
Add harddrop support (kernel support added a long time ago), and various
cleanups.
min BYTES, max BYTES are now optional and follow Sally Floyd's
recommendations.
By the way, our default 2% probability is a bit low, Sally recommends 10%.
Not a big deal if upcoming adaptative algo is deployed.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
diff --git a/tc/q_red.c b/tc/q_red.c
index 6e58d7a..18020d7 100644
--- a/tc/q_red.c
+++ b/tc/q_red.c
@@ -27,8 +27,8 @@
static void explain(void)
{
- fprintf(stderr, "Usage: ... red limit BYTES min BYTES max BYTES avpkt BYTES burst PACKETS\n");
- fprintf(stderr, " probability PROBABILITY bandwidth KBPS [ ecn ]\n");
+ fprintf(stderr, "Usage: ... red limit BYTES [min BYTES] [max BYTES] avpkt BYTES [burst PACKETS]\n");
+ fprintf(stderr, " [probability PROBABILITY] bandwidth KBPS [ecn] [harddrop]\n");
}
static int red_parse_opt(struct qdisc_util *qu, int argc, char **argv, struct nlmsghdr *n)
@@ -38,7 +38,6 @@
unsigned avpkt = 0;
double probability = 0.02;
unsigned rate = 0;
- int ecn_ok = 0;
int wlog;
__u8 sbuf[256];
struct rtattr *tail;
@@ -89,7 +88,9 @@
return -1;
}
} else if (strcmp(*argv, "ecn") == 0) {
- ecn_ok = 1;
+ opt.flags |= TC_RED_ECN;
+ } else if (strcmp(*argv, "harddrop") == 0) {
+ opt.flags |= TC_RED_HARDDROP;
} else if (strcmp(*argv, "help") == 0) {
explain();
return -1;
@@ -104,14 +105,20 @@
if (rate == 0)
get_rate(&rate, "10Mbit");
- if (!opt.qth_min || !opt.qth_max || !opt.limit || !avpkt) {
- fprintf(stderr, "RED: Required parameter (min, max, limit, avpkt) is missing\n");
+ if (!opt.limit || !avpkt) {
+ fprintf(stderr, "RED: Required parameter (limit, avpkt) is missing\n");
return -1;
}
- if (!burst) {
+ /* Compute default min/max thresholds based on
+ * Sally Floyd's recommendations:
+ * http://www.icir.org/floyd/REDparameters.txt
+ */
+ if (!opt.qth_max)
+ opt.qth_max = opt.qth_min ? opt.qth_min * 3 : opt.limit / 4;
+ if (!opt.qth_min)
+ opt.qth_min = opt.qth_max / 3;
+ if (!burst)
burst = (2 * opt.qth_min + opt.qth_max) / (3 * avpkt);
- fprintf(stderr, "RED: set burst to %u\n", burst);
- }
if ((wlog = tc_red_eval_ewma(opt.qth_min, burst, avpkt)) < 0) {
fprintf(stderr, "RED: failed to calculate EWMA constant.\n");
return -1;
@@ -129,14 +136,6 @@
return -1;
}
opt.Scell_log = wlog;
- if (ecn_ok) {
-#ifdef TC_RED_ECN
- opt.flags |= TC_RED_ECN;
-#else
- fprintf(stderr, "RED: ECN support is missing in this binary.\n");
- return -1;
-#endif
- }
tail = NLMSG_TAIL(n);
addattr_l(n, 1024, TCA_OPTIONS, NULL, 0);
@@ -148,7 +147,7 @@
static int red_print_opt(struct qdisc_util *qu, FILE *f, struct rtattr *opt)
{
- struct rtattr *tb[TCA_RED_STAB+1];
+ struct rtattr *tb[TCA_RED_MAX + 1];
struct tc_red_qopt *qopt;
SPRINT_BUF(b1);
SPRINT_BUF(b2);
@@ -157,7 +156,7 @@
if (opt == NULL)
return 0;
- parse_rtattr_nested(tb, TCA_RED_STAB, opt);
+ parse_rtattr_nested(tb, TCA_RED_MAX, opt);
if (tb[TCA_RED_PARMS] == NULL)
return -1;
@@ -168,10 +167,10 @@
sprint_size(qopt->limit, b1),
sprint_size(qopt->qth_min, b2),
sprint_size(qopt->qth_max, b3));
-#ifdef TC_RED_ECN
if (qopt->flags & TC_RED_ECN)
fprintf(f, "ecn ");
-#endif
+ if (qopt->flags & TC_RED_HARDDROP)
+ fprintf(f, "harddrop ");
if (show_details) {
fprintf(f, "ewma %u Plog %u Scell_log %u",
qopt->Wlog, qopt->Plog, qopt->Scell_log);
