[Cake] progress? dual-src/dsthost unfairness
George Amanakis
gamanakis at gmail.com
Thu Feb 14 13:02:17 EST 2019
I tried Toke's and Jonathan's suggestion, dropping the
sparse_flow_count. Tthe results are the same (fairness).
In a hash collision in this patch the host_bulk_flow_count is not updated,
does this make sense?
-------------------8<-------------------
Client A:
Data file written to ./tcp_8down-2019-02-14T115248.702453.flent.gz.
Summary of tcp_8down test run at 2019-02-14 16:52:48.702453:
avg median # data pts
Ping (ms) ICMP : 0.78 0.69 ms 341
TCP download avg : 6.00 5.81 Mbits/s 301
TCP download sum : 48.00 46.51 Mbits/s 301
TCP download::1 : 6.00 5.82 Mbits/s 297
TCP download::2 : 5.99 5.82 Mbits/s 297
TCP download::3 : 6.00 5.82 Mbits/s 297
TCP download::4 : 6.00 5.82 Mbits/s 297
TCP download::5 : 6.00 5.82 Mbits/s 297
TCP download::6 : 6.00 5.82 Mbits/s 298
TCP download::7 : 6.01 5.82 Mbits/s 297
TCP download::8 : 6.00 5.82 Mbits/s 298
Data file written to ./tcp_1up-2019-02-14T115249.700445.flent.gz.
Summary of tcp_1up test run at 2019-02-14 16:52:49.700445:
avg median # data pts
Ping (ms) ICMP : 0.79 0.69 ms 341
TCP upload : 47.69 46.33 Mbits/s 266
Client B:
Data file written to ./tcp_1down-2019-02-14T115250.817948.flent.gz.
Summary of tcp_1down test run at 2019-02-14 16:52:50.817948:
avg median # data pts
Ping (ms) ICMP : 0.83 0.69 ms 341
TCP download : 47.82 46.57 Mbits/s 300
Data file written to ./tcp_8up-2019-02-14T115251.710755.flent.gz.
Summary of tcp_8up test run at 2019-02-14 16:52:51.710755:
avg median # data pts
Ping (ms) ICMP : 0.78 0.69 ms 341
TCP upload avg : 5.99 5.79 Mbits/s 301
TCP upload sum : 47.88 46.30 Mbits/s 301
TCP upload::1 : 5.98 5.81 Mbits/s 224
TCP upload::2 : 5.99 5.82 Mbits/s 224
TCP upload::3 : 5.98 5.77 Mbits/s 219
TCP upload::4 : 5.98 5.82 Mbits/s 224
TCP upload::5 : 5.99 5.77 Mbits/s 218
TCP upload::6 : 5.99 5.77 Mbits/s 221
TCP upload::7 : 5.98 5.77 Mbits/s 219
TCP upload::8 : 5.99 5.77 Mbits/s 221
-------------------8<-------------------
---
sch_cake.c | 84 +++++++++++++++++++++++++++++++++++-------------------
1 file changed, 55 insertions(+), 29 deletions(-)
diff --git a/sch_cake.c b/sch_cake.c
index d434ae0..ed3fbd9 100644
--- a/sch_cake.c
+++ b/sch_cake.c
@@ -146,8 +146,8 @@ 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;
};
struct cake_heap_entry {
@@ -844,8 +844,6 @@ 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 +863,12 @@ 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)
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 +884,12 @@ 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)
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;
}
}
@@ -1913,20 +1909,30 @@ static s32 cake_enqueue(struct sk_buff *skb, struct Qdisc *sch,
b->sparse_flow_count++;
if (cake_dsrc(q->flow_mode))
- host_load = max(host_load, srchost->srchost_refcnt);
+ host_load = max(host_load, srchost->srchost_bulk_flow_count);
if (cake_ddst(q->flow_mode))
- host_load = max(host_load, dsthost->dsthost_refcnt);
+ host_load = max(host_load, dsthost->dsthost_bulk_flow_count);
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_bulk_flow_count++;
+
+ if (cake_ddst(q->flow_mode))
+ dsthost->dsthost_bulk_flow_count++;
+
}
if (q->buffer_used > q->buffer_max_used)
@@ -2097,23 +2103,8 @@ 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 +2113,13 @@ retry:
if (flow->head) {
b->sparse_flow_count--;
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++;
+
flow->set = CAKE_SET_BULK;
} else {
/* we've moved it to the bulk rotation for
@@ -2131,6 +2129,22 @@ 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;
}
@@ -2151,6 +2165,13 @@ 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) {
@@ -2164,14 +2185,19 @@ retry:
if (flow->set == CAKE_SET_SPARSE ||
flow->set == CAKE_SET_SPARSE_WAIT)
b->sparse_flow_count--;
- else if (flow->set == CAKE_SET_BULK)
+ 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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