This is not intented to go to mainline, provided just for those
who are interested enough about the algorithm internals during
a test.
Signed-off-by: Ilpo Järvinen <[EMAIL PROTECTED]>
---
include/linux/snmp.h | 20 +++++++++++++++++++
net/ipv4/proc.c | 20 +++++++++++++++++++
net/ipv4/tcp_input.c | 52 +++++++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 89 insertions(+), 3 deletions(-)
diff --git a/include/linux/snmp.h b/include/linux/snmp.h
index 89f0c2b..42b8c07 100644
--- a/include/linux/snmp.h
+++ b/include/linux/snmp.h
@@ -214,6 +214,26 @@ enum
LINUX_MIB_TCPDSACKIGNOREDOLD, /* TCPSACKIgnoredOld */
LINUX_MIB_TCPDSACKIGNOREDNOUNDO, /* TCPSACKIgnoredNoUndo */
LINUX_MIB_TCPSPURIOUSRTOS, /* TCPSpuriousRTOs */
+ LINUX_MIB_TCP_SACKTAG,
+ LINUX_MIB_TCP_SACK0,
+ LINUX_MIB_TCP_SACK1,
+ LINUX_MIB_TCP_SACK2,
+ LINUX_MIB_TCP_SACK3,
+ LINUX_MIB_TCP_SACK4,
+ LINUX_MIB_TCP_WALKEDSKBS,
+ LINUX_MIB_TCP_WALKEDDSACKS,
+ LINUX_MIB_TCP_SKIPPEDSKBS,
+ LINUX_MIB_TCP_NOCACHE,
+ LINUX_MIB_TCP_FULLWALK,
+ LINUX_MIB_TCP_HEADWALK,
+ LINUX_MIB_TCP_TAILWALK,
+ LINUX_MIB_TCP_FULLSKIP,
+ LINUX_MIB_TCP_TAILSKIP,
+ LINUX_MIB_TCP_HEADSKIP,
+ LINUX_MIB_TCP_FULLSKIP_TOHIGH,
+ LINUX_MIB_TCP_TAILSKIP_TOHIGH,
+ LINUX_MIB_TCP_NEWSKIP,
+ LINUX_MIB_TCP_CACHEREMAINING,
__LINUX_MIB_MAX
};
diff --git a/net/ipv4/proc.c b/net/ipv4/proc.c
index e5b05b0..9909178 100644
--- a/net/ipv4/proc.c
+++ b/net/ipv4/proc.c
@@ -246,6 +246,26 @@ static const struct snmp_mib snmp4_net_list[] = {
SNMP_MIB_ITEM("TCPDSACKIgnoredOld", LINUX_MIB_TCPDSACKIGNOREDOLD),
SNMP_MIB_ITEM("TCPDSACKIgnoredNoUndo", LINUX_MIB_TCPDSACKIGNOREDNOUNDO),
SNMP_MIB_ITEM("TCPSpuriousRTOs", LINUX_MIB_TCPSPURIOUSRTOS),
+ SNMP_MIB_ITEM("TCP_SACKTAG", LINUX_MIB_TCP_SACKTAG),
+ SNMP_MIB_ITEM("TCP_SACK0", LINUX_MIB_TCP_SACK0),
+ SNMP_MIB_ITEM("TCP_SACK1", LINUX_MIB_TCP_SACK1),
+ SNMP_MIB_ITEM("TCP_SACK2", LINUX_MIB_TCP_SACK2),
+ SNMP_MIB_ITEM("TCP_SACK3", LINUX_MIB_TCP_SACK3),
+ SNMP_MIB_ITEM("TCP_SACK4", LINUX_MIB_TCP_SACK4),
+ SNMP_MIB_ITEM("TCP_WALKEDSKBS", LINUX_MIB_TCP_WALKEDSKBS),
+ SNMP_MIB_ITEM("TCP_WALKEDDSACKS", LINUX_MIB_TCP_WALKEDDSACKS),
+ SNMP_MIB_ITEM("TCP_SKIPPEDSKBS", LINUX_MIB_TCP_SKIPPEDSKBS),
+ SNMP_MIB_ITEM("TCP_NOCACHE", LINUX_MIB_TCP_NOCACHE),
+ SNMP_MIB_ITEM("TCP_FULLWALK", LINUX_MIB_TCP_FULLWALK),
+ SNMP_MIB_ITEM("TCP_HEADWALK", LINUX_MIB_TCP_HEADWALK),
+ SNMP_MIB_ITEM("TCP_TAILWALK", LINUX_MIB_TCP_TAILWALK),
+ SNMP_MIB_ITEM("TCP_FULLSKIP", LINUX_MIB_TCP_FULLSKIP),
+ SNMP_MIB_ITEM("TCP_TAILSKIP", LINUX_MIB_TCP_TAILSKIP),
+ SNMP_MIB_ITEM("TCP_HEADSKIP", LINUX_MIB_TCP_HEADSKIP),
+ SNMP_MIB_ITEM("TCP_FULLSKIP_TOHIGH", LINUX_MIB_TCP_FULLSKIP_TOHIGH),
+ SNMP_MIB_ITEM("TCP_TAILSKIP_TOHIGH", LINUX_MIB_TCP_TAILSKIP_TOHIGH),
+ SNMP_MIB_ITEM("TCP_NEWSKIP", LINUX_MIB_TCP_NEWSKIP),
+ SNMP_MIB_ITEM("TCP_CACHEREMAINING", LINUX_MIB_TCP_CACHEREMAINING),
SNMP_MIB_SENTINEL
};
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index c13f1af..02b34a5 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1382,6 +1382,10 @@ static struct sk_buff *tcp_sacktag_walk(struct sk_buff
*skb, struct sock *sk,
tcp_sacktag_one(skb, sk, state, in_sack, dup_sack,
state->fack_count, end_seq);
+
+ NET_INC_STATS_BH(LINUX_MIB_TCP_WALKEDSKBS);
+ if (dup_sack)
+ NET_INC_STATS_BH(LINUX_MIB_TCP_WALKEDDSACKS);
}
return skb;
}
@@ -1405,6 +1409,7 @@ static struct sk_buff *tcp_sacktag_skip(struct sk_buff
*skb, struct sock *sk,
skb = tcp_sacktag_walk(skb, sk, state, state->dup_start,
state->dup_end, 1);
}
+ NET_INC_STATS_BH(LINUX_MIB_TCP_SKIPPEDSKBS);
}
return skb;
}
@@ -1535,9 +1540,22 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff
*ack_skb, u32 prior_snd_
cache++;
}
+ NET_INC_STATS_BH(LINUX_MIB_TCP_SACKTAG);
+ switch (used_sacks) {
+ case 0: NET_INC_STATS_BH(LINUX_MIB_TCP_SACK0); break;
+ case 1: NET_INC_STATS_BH(LINUX_MIB_TCP_SACK1); break;
+ case 2: NET_INC_STATS_BH(LINUX_MIB_TCP_SACK2); break;
+ case 3: NET_INC_STATS_BH(LINUX_MIB_TCP_SACK3); break;
+ case 4: NET_INC_STATS_BH(LINUX_MIB_TCP_SACK4); break;
+ }
+
+ if (!tcp_sack_cache_ok(tp, cache))
+ NET_INC_STATS_BH(LINUX_MIB_TCP_NOCACHE);
+
while (i < used_sacks) {
u32 start_seq = sp[i].start_seq;
u32 end_seq = sp[i].end_seq;
+ int fullwalk = 0;
/* Event "B" in the comment above. */
if (after(end_seq, tp->high_seq))
@@ -1550,41 +1568,69 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff
*ack_skb, u32 prior_snd_
if (tcp_sack_cache_ok(tp, cache)) {
if (after(end_seq, cache->start_seq)) {
+ int headskip = 0;
+
if (before(start_seq, cache->start_seq)) {
skb = tcp_sacktag_skip(skb, sk, &state,
start_seq);
skb = tcp_sacktag_walk(skb, sk, &state,
start_seq, cache->start_seq, 0);
- }
+
NET_INC_STATS_BH(LINUX_MIB_TCP_HEADWALK);
+ } else
+ headskip = 1;
+
/* Rest of the block already fully processed? */
if (!after(end_seq, cache->end_seq)) {
i++;
+ if (headskip)
+
NET_INC_STATS_BH(LINUX_MIB_TCP_FULLSKIP);
+ else
+
NET_INC_STATS_BH(LINUX_MIB_TCP_TAILSKIP);
continue;
}
+
if (TCP_SKB_CB(tp->highest_sack)->end_seq !=
cache->end_seq) {
skb = tcp_sacktag_skip(skb, sk, &state,
cache->end_seq);
cache++;
+ if (headskip)
+
NET_INC_STATS_BH(LINUX_MIB_TCP_HEADSKIP);
continue;
}
skb = tcp_sacktag_skip_to_highsack(skb, sk,
&state, cache);
- }
+ if (headskip)
+
NET_INC_STATS_BH(LINUX_MIB_TCP_FULLSKIP_TOHIGH);
+ else
+
NET_INC_STATS_BH(LINUX_MIB_TCP_TAILSKIP_TOHIGH);
+ } else
+ fullwalk = 1;
} else if (!before(start_seq, tcp_highest_sack_seq(sk)) &&
before(TCP_SKB_CB(skb)->seq,
tcp_highest_sack_seq(sk))) {
skb = tcp_write_queue_next(sk, tp->highest_sack);
state.fack_count = tp->fackets_out;
+ NET_INC_STATS_BH(LINUX_MIB_TCP_NEWSKIP);
+ fullwalk = 1;
}
skb = tcp_sacktag_skip(skb, sk, &state, start_seq);
skb = tcp_sacktag_walk(skb, sk, &state, start_seq, end_seq, 0);
+ if (fullwalk)
+ NET_INC_STATS_BH(LINUX_MIB_TCP_FULLWALK);
+ else
+ NET_INC_STATS_BH(LINUX_MIB_TCP_TAILWALK);
i++;
}
+ if (tcp_sack_cache_ok(tp, cache))
+ NET_INC_STATS_BH(LINUX_MIB_TCP_CACHEREMAINING);
+
/* Clear the head of the cache sack blocks so we can skip it next time
*/
for (i = 0; i < ARRAY_SIZE(tp->recv_sack_cache) - used_sacks; i++) {
tp->recv_sack_cache[i].start_seq = 0;
tp->recv_sack_cache[i].end_seq = 0;
}
- for (j = 0; j < used_sacks; j++)
+ for (j = 0; j < used_sacks; j++) {
+ WARN_ON(i >= ARRAY_SIZE(tp->recv_sack_cache));
tp->recv_sack_cache[i++] = sp[j];
+ }
if (tp->retrans_out &&
after(state.highest_sack_end_seq, tp->lost_retrans_low) &&
--
1.5.0.6
-
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