[Cake] progress? dual-src/dsthost unfairness
George Amanakis
gamanakis at gmail.com
Wed Feb 13 15:55:59 EST 2019
Updated version with Jonathan's suggestion. Fairness is preserved.
enp4s0 enp1s0
Client A/B <------> router <------> server
tc qdisc add dev enp1s0 root cake bandwidth 100mbit dual-srchost
besteffort
tc qdisc add dev enp4s0 root cake bandwidth 100mbit dual-dsthost
besteffort
-----------8<-----------
Client A:
Data file written to ./tcp_8down-2019-02-13T150846.110370.flent.gz.
Summary of tcp_8down test run at 2019-02-13 20:08:46.110370:
avg median # data pts
Ping (ms) ICMP : 0.82 0.66 ms 340
TCP download avg : 5.97 5.80 Mbits/s 301
TCP download sum : 47.73 46.42 Mbits/s 301
TCP download::1 : 5.96 5.82 Mbits/s 297
TCP download::2 : 5.96 5.82 Mbits/s 298
TCP download::3 : 5.97 5.82 Mbits/s 297
TCP download::4 : 5.96 5.82 Mbits/s 297
TCP download::5 : 5.97 5.82 Mbits/s 297
TCP download::6 : 5.97 5.82 Mbits/s 297
TCP download::7 : 5.97 5.82 Mbits/s 297
TCP download::8 : 5.97 5.82 Mbits/s 297
Data file written to ./tcp_1up-2019-02-13T150847.148563.flent.gz.
Summary of tcp_1up test run at 2019-02-13 20:08:47.148563:
avg median # data pts
Ping (ms) ICMP : 0.87 0.68 ms 340
TCP upload : 47.46 46.39 Mbits/s 265
Client B:
Data file written to ./tcp_1down-2019-02-13T150848.112225.flent.gz.
Summary of tcp_1down test run at 2019-02-13 20:08:48.112225:
avg median # data pts
Ping (ms) ICMP : 0.75 0.65 ms 340
TCP download : 47.50 46.57 Mbits/s 300
Data file written to ./tcp_8up-2019-02-13T150849.120750.flent.gz.
Summary of tcp_8up test run at 2019-02-13 20:08:49.120750:
avg median # data pts
Ping (ms) ICMP : 0.79 0.68 ms 340
TCP upload avg : 5.95 5.78 Mbits/s 301
TCP upload sum : 47.61 46.23 Mbits/s 301
TCP upload::1 : 5.97 5.82 Mbits/s 171
TCP upload::2 : 5.95 5.83 Mbits/s 224
TCP upload::3 : 5.95 5.81 Mbits/s 223
TCP upload::4 : 5.95 5.82 Mbits/s 224
TCP upload::5 : 5.94 5.82 Mbits/s 223
TCP upload::6 : 5.95 5.76 Mbits/s 275
TCP upload::7 : 5.95 5.77 Mbits/s 222
TCP upload::8 : 5.95 5.77 Mbits/s 221
-----------8<-----------
---
sch_cake.c | 125 +++++++++++++++++++++++++++++++++++++++--------------
1 file changed, 93 insertions(+), 32 deletions(-)
diff --git a/sch_cake.c b/sch_cake.c
index d434ae0..7567378 100644
--- a/sch_cake.c
+++ b/sch_cake.c
@@ -146,8 +146,10 @@ struct cake_flow {
struct cake_host {
u32 srchost_tag;
u32 dsthost_tag;
- u16 srchost_refcnt;
- u16 dsthost_refcnt;
+ u16 srchost_bulk_flow_count;
+ u16 dsthost_bulk_flow_count;
+ u16 srchost_sparse_flow_count;
+ u16 dsthost_sparse_flow_count;
};
struct cake_heap_entry {
@@ -844,8 +846,6 @@ skip_hash:
* queue, accept the collision, update the host tags.
*/
q->way_collisions++;
- q->hosts[q->flows[reduced_hash].srchost].srchost_refcnt--;
- q->hosts[q->flows[reduced_hash].dsthost].dsthost_refcnt--;
allocate_src = cake_dsrc(flow_mode);
allocate_dst = cake_ddst(flow_mode);
found:
@@ -865,13 +865,13 @@ found:
}
for (i = 0; i < CAKE_SET_WAYS;
i++, k = (k + 1) % CAKE_SET_WAYS) {
- if (!q->hosts[outer_hash + k].srchost_refcnt)
+ if (!q->hosts[outer_hash + k].srchost_bulk_flow_count &&
+ !q->hosts[outer_hash + k].srchost_sparse_flow_count)
break;
}
q->hosts[outer_hash + k].srchost_tag = srchost_hash;
found_src:
srchost_idx = outer_hash + k;
- q->hosts[srchost_idx].srchost_refcnt++;
q->flows[reduced_hash].srchost = srchost_idx;
}
@@ -887,13 +887,13 @@ found_src:
}
for (i = 0; i < CAKE_SET_WAYS;
i++, k = (k + 1) % CAKE_SET_WAYS) {
- if (!q->hosts[outer_hash + k].dsthost_refcnt)
+ if (!q->hosts[outer_hash + k].dsthost_bulk_flow_count &&
+ !q->hosts[outer_hash + k].dsthost_sparse_flow_count)
break;
}
q->hosts[outer_hash + k].dsthost_tag = dsthost_hash;
found_dst:
dsthost_idx = outer_hash + k;
- q->hosts[dsthost_idx].dsthost_refcnt++;
q->flows[reduced_hash].dsthost = dsthost_idx;
}
}
@@ -1901,6 +1901,7 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
if (!flow->set || flow->set == CAKE_SET_DECAYING) {
struct cake_host *srchost = &b->hosts[flow->srchost];
struct cake_host *dsthost = &b->hosts[flow->dsthost];
+ u16 sum;
u16 host_load = 1;
if (!flow->set) {
@@ -1912,21 +1913,43 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
flow->set = CAKE_SET_SPARSE;
b->sparse_flow_count++;
- if (cake_dsrc(q->flow_mode))
- host_load = max(host_load, srchost->srchost_refcnt);
+ if (cake_dsrc(q->flow_mode)) {
+ srchost->srchost_sparse_flow_count++;
+ sum = srchost->srchost_sparse_flow_count +
+ srchost->srchost_bulk_flow_count;
+ host_load = max(host_load, sum);
+ }
- if (cake_ddst(q->flow_mode))
- host_load = max(host_load, dsthost->dsthost_refcnt);
+ if (cake_ddst(q->flow_mode)) {
+ dsthost->dsthost_sparse_flow_count++;
+ sum = dsthost->dsthost_sparse_flow_count +
+ dsthost->dsthost_bulk_flow_count;
+ host_load = max(host_load, sum);
+ }
flow->deficit = (b->flow_quantum *
quantum_div[host_load]) >> 16;
} else if (flow->set == CAKE_SET_SPARSE_WAIT) {
+ struct cake_host *srchost = &b->hosts[flow->srchost];
+ struct cake_host *dsthost = &b->hosts[flow->dsthost];
+
/* this flow was empty, accounted as a sparse flow, but actually
* in the bulk rotation.
*/
flow->set = CAKE_SET_BULK;
b->sparse_flow_count--;
b->bulk_flow_count++;
+
+ if (cake_dsrc(q->flow_mode)) {
+ srchost->srchost_sparse_flow_count--;
+ srchost->srchost_bulk_flow_count++;
+ }
+
+ if (cake_ddst(q->flow_mode)) {
+ dsthost->dsthost_sparse_flow_count--;
+ dsthost->dsthost_bulk_flow_count++;
+ }
+
}
if (q->buffer_used > q->buffer_max_used)
@@ -2097,23 +2120,8 @@ retry:
dsthost = &b->hosts[flow->dsthost];
host_load = 1;
- if (cake_dsrc(q->flow_mode))
- host_load = max(host_load, srchost->srchost_refcnt);
-
- if (cake_ddst(q->flow_mode))
- host_load = max(host_load, dsthost->dsthost_refcnt);
-
- WARN_ON(host_load > CAKE_QUEUES);
-
/* flow isolation (DRR++) */
if (flow->deficit <= 0) {
- /* The shifted prandom_u32() is a way to apply dithering to
- * avoid accumulating roundoff errors
- */
- flow->deficit += (b->flow_quantum * quantum_div[host_load] +
- (prandom_u32() >> 16)) >> 16;
- list_move_tail(&flow->flowchain, &b->old_flows);
-
/* Keep all flows with deficits out of the sparse and decaying
* rotations. No non-empty flow can go into the decaying
* rotation, so they can't get deficits
@@ -2122,6 +2130,17 @@ retry:
if (flow->head) {
b->sparse_flow_count--;
b->bulk_flow_count++;
+
+ if (cake_dsrc(q->flow_mode)) {
+ srchost->srchost_sparse_flow_count--;
+ srchost->srchost_bulk_flow_count++;
+ }
+
+ if (cake_ddst(q->flow_mode)) {
+ dsthost->dsthost_sparse_flow_count--;
+ dsthost->dsthost_bulk_flow_count++;
+ }
+
flow->set = CAKE_SET_BULK;
} else {
/* we've moved it to the bulk rotation for
@@ -2131,6 +2150,22 @@ retry:
flow->set = CAKE_SET_SPARSE_WAIT;
}
}
+
+ if (cake_dsrc(q->flow_mode))
+ host_load = max(host_load, srchost->srchost_bulk_flow_count);
+
+ if (cake_ddst(q->flow_mode))
+ host_load = max(host_load, dsthost->dsthost_bulk_flow_count);
+
+ WARN_ON(host_load > CAKE_QUEUES);
+
+ /* The shifted prandom_u32() is a way to apply dithering to
+ * avoid accumulating roundoff errors
+ */
+ flow->deficit += (b->flow_quantum * quantum_div[host_load] +
+ (prandom_u32() >> 16)) >> 16;
+ list_move_tail(&flow->flowchain, &b->old_flows);
+
goto retry;
}
@@ -2151,10 +2186,24 @@ retry:
&b->decaying_flows);
if (flow->set == CAKE_SET_BULK) {
b->bulk_flow_count--;
+
+ if (cake_dsrc(q->flow_mode))
+ srchost->srchost_bulk_flow_count--;
+
+ if (cake_ddst(q->flow_mode))
+ dsthost->dsthost_bulk_flow_count--;
+
b->decaying_flow_count++;
} else if (flow->set == CAKE_SET_SPARSE ||
flow->set == CAKE_SET_SPARSE_WAIT) {
b->sparse_flow_count--;
+
+ if (cake_dsrc(q->flow_mode))
+ srchost->srchost_sparse_flow_count--;
+
+ if (cake_ddst(q->flow_mode))
+ dsthost->dsthost_sparse_flow_count--;
+
b->decaying_flow_count++;
}
flow->set = CAKE_SET_DECAYING;
@@ -2162,16 +2211,28 @@ retry:
/* remove empty queue from the flowchain */
list_del_init(&flow->flowchain);
if (flow->set == CAKE_SET_SPARSE ||
- flow->set == CAKE_SET_SPARSE_WAIT)
+ flow->set == CAKE_SET_SPARSE_WAIT) {
b->sparse_flow_count--;
- else if (flow->set == CAKE_SET_BULK)
+
+ if (cake_dsrc(q->flow_mode))
+ srchost->srchost_sparse_flow_count--;
+
+ if (cake_ddst(q->flow_mode))
+ dsthost->dsthost_sparse_flow_count--;
+
+ } else if (flow->set == CAKE_SET_BULK) {
b->bulk_flow_count--;
- else
+
+ if (cake_dsrc(q->flow_mode))
+ srchost->srchost_bulk_flow_count--;
+
+ if (cake_ddst(q->flow_mode))
+ dsthost->dsthost_bulk_flow_count--;
+
+ } else
b->decaying_flow_count--;
flow->set = CAKE_SET_NONE;
- srchost->srchost_refcnt--;
- dsthost->dsthost_refcnt--;
}
goto begin;
}
--
2.20.1
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