mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-21 16:29:59 +00:00
dccp tfrc: Let dccp_tfrc_lib do the sampling work
This migrates more TFRC-related code into the dccp_tfrc_lib: * sampling of the packet size `s' (which is only needed until the first loss interval is computed (ccid3_first_li)); * updating the byte-counter `bytes_recvd' in between sending feedbacks. The result is a better separation of CCID-3 specific and TFRC specific code, which aids future integration with ECN and e.g. CCID-4. Further changes: ---------------- * replaced magic number of 536 with equivalent constant TCP_MIN_RCVMSS; (this constant is also used when no estimate for `s' is available). Signed-off-by: Gerrit Renker <gerrit@erg.abdn.ac.uk>
This commit is contained in:
parent
3ca7aea041
commit
34a081be8e
5 changed files with 35 additions and 35 deletions
|
@ -590,12 +590,9 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
|
|||
* would bring X down to s/t_mbi. That is why we return
|
||||
* X_recv according to rfc3448bis-06 for the moment.
|
||||
*/
|
||||
u32 rtt = hcrx->rtt ? : DCCP_FALLBACK_RTT, s = hcrx->s;
|
||||
u32 rtt = hcrx->rtt ? : DCCP_FALLBACK_RTT,
|
||||
s = tfrc_rx_hist_packet_size(&hcrx->hist);
|
||||
|
||||
if (s == 0) {
|
||||
DCCP_WARN("No sample for s, using fallback\n");
|
||||
s = TCP_MIN_RCVMSS;
|
||||
}
|
||||
hcrx->x_recv = scaled_div32(s, 2 * rtt);
|
||||
break;
|
||||
}
|
||||
|
@ -617,7 +614,7 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
|
|||
if (delta <= 0)
|
||||
DCCP_BUG("delta (%ld) <= 0", (long)delta);
|
||||
else
|
||||
hcrx->x_recv = scaled_div32(hcrx->bytes_recv, delta);
|
||||
hcrx->x_recv = scaled_div32(hcrx->hist.bytes_recvd, delta);
|
||||
break;
|
||||
default:
|
||||
return;
|
||||
|
@ -628,7 +625,7 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk,
|
|||
|
||||
hcrx->tstamp_last_feedback = now;
|
||||
hcrx->last_counter = dccp_hdr(skb)->dccph_ccval;
|
||||
hcrx->bytes_recv = 0;
|
||||
hcrx->hist.bytes_recvd = 0;
|
||||
|
||||
dp->dccps_hc_rx_insert_options = 1;
|
||||
dccp_send_ack(sk);
|
||||
|
@ -669,7 +666,8 @@ static int ccid3_hc_rx_insert_options(struct sock *sk, struct sk_buff *skb)
|
|||
static u32 ccid3_first_li(struct sock *sk)
|
||||
{
|
||||
struct ccid3_hc_rx_sock *hcrx = ccid3_hc_rx_sk(sk);
|
||||
u32 x_recv, p, delta;
|
||||
u32 x_recv, p, delta,
|
||||
s = tfrc_rx_hist_packet_size(&hcrx->hist);
|
||||
u64 fval;
|
||||
|
||||
/*
|
||||
|
@ -686,7 +684,7 @@ static u32 ccid3_first_li(struct sock *sk)
|
|||
}
|
||||
|
||||
delta = ktime_to_us(net_timedelta(hcrx->tstamp_last_feedback));
|
||||
x_recv = scaled_div32(hcrx->bytes_recv, delta);
|
||||
x_recv = scaled_div32(hcrx->hist.bytes_recvd, delta);
|
||||
if (x_recv == 0) { /* would also trigger divide-by-zero */
|
||||
DCCP_WARN("X_recv==0\n");
|
||||
if (hcrx->x_recv == 0) {
|
||||
|
@ -696,8 +694,7 @@ static u32 ccid3_first_li(struct sock *sk)
|
|||
x_recv = hcrx->x_recv;
|
||||
}
|
||||
|
||||
fval = scaled_div(hcrx->s, hcrx->rtt);
|
||||
fval = scaled_div32(fval, x_recv);
|
||||
fval = scaled_div32(scaled_div(s, hcrx->rtt), x_recv);
|
||||
p = tfrc_calc_x_reverse_lookup(fval);
|
||||
|
||||
ccid3_pr_debug("%s(%p), receive rate=%u bytes/s, implied "
|
||||
|
@ -724,31 +721,12 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb)
|
|||
|
||||
if (unlikely(hcrx->state == TFRC_RSTATE_NO_DATA)) {
|
||||
if (is_data_packet) {
|
||||
const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
|
||||
do_feedback = CCID3_FBACK_INITIAL;
|
||||
ccid3_hc_rx_set_state(sk, TFRC_RSTATE_DATA);
|
||||
hcrx->s = payload;
|
||||
/*
|
||||
* Not necessary to update bytes_recv here,
|
||||
* since X_recv = 0 for the first feedback packet (cf.
|
||||
* RFC 3448, 6.3) -- gerrit
|
||||
*/
|
||||
}
|
||||
goto update_records;
|
||||
}
|
||||
|
||||
if (tfrc_rx_hist_duplicate(&hcrx->hist, skb))
|
||||
return; /* done receiving */
|
||||
|
||||
if (is_data_packet) {
|
||||
const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
|
||||
/*
|
||||
* Update moving-average of s and the sum of received payload bytes
|
||||
*/
|
||||
hcrx->s = tfrc_ewma(hcrx->s, payload, 9);
|
||||
hcrx->bytes_recv += payload;
|
||||
}
|
||||
|
||||
if (tfrc_rx_hist_loss_pending(&hcrx->hist))
|
||||
return; /* done receiving */
|
||||
|
||||
|
|
|
@ -124,25 +124,21 @@ enum ccid3_hc_rx_states {
|
|||
*
|
||||
* @last_counter - Tracks window counter (RFC 4342, 8.1)
|
||||
* @state - Receiver state, one of %ccid3_hc_rx_states
|
||||
* @bytes_recv - Total sum of DCCP payload bytes
|
||||
* @x_recv - Receiver estimate of send rate (RFC 3448, sec. 4.3)
|
||||
* @rtt - Receiver estimate of RTT
|
||||
* @tstamp_last_feedback - Time at which last feedback was sent
|
||||
* @hist - Packet history (loss detection + RTT sampling)
|
||||
* @li_hist - Loss Interval database
|
||||
* @s - Received packet size in bytes
|
||||
* @p_inverse - Inverse of Loss Event Rate (RFC 4342, sec. 8.5)
|
||||
*/
|
||||
struct ccid3_hc_rx_sock {
|
||||
u8 last_counter:4;
|
||||
enum ccid3_hc_rx_states state:8;
|
||||
u32 bytes_recv;
|
||||
u32 x_recv;
|
||||
u32 rtt;
|
||||
ktime_t tstamp_last_feedback;
|
||||
struct tfrc_rx_hist hist;
|
||||
struct tfrc_loss_hist li_hist;
|
||||
u16 s;
|
||||
#define p_inverse li_hist.i_mean
|
||||
};
|
||||
|
||||
|
|
|
@ -352,6 +352,16 @@ int tfrc_rx_handle_loss(struct tfrc_rx_hist *h,
|
|||
__three_after_loss(h);
|
||||
}
|
||||
|
||||
/*
|
||||
* Update moving-average of `s' and the sum of received payload bytes.
|
||||
*/
|
||||
if (dccp_data_packet(skb)) {
|
||||
const u32 payload = skb->len - dccp_hdr(skb)->dccph_doff * 4;
|
||||
|
||||
h->packet_size = tfrc_ewma(h->packet_size, payload, 9);
|
||||
h->bytes_recvd += payload;
|
||||
}
|
||||
|
||||
/* RFC 3448, 6.1: update I_0, whose growth implies p <= p_prev */
|
||||
if (!is_new_loss)
|
||||
tfrc_lh_update_i_mean(lh, skb);
|
||||
|
|
|
@ -91,12 +91,16 @@ struct tfrc_rx_hist_entry {
|
|||
* @loss_count: Number of entries in circular history
|
||||
* @loss_start: Movable index (for loss detection)
|
||||
* @rtt_sample_prev: Used during RTT sampling, points to candidate entry
|
||||
* @packet_size: Packet size in bytes (as per RFC 3448, 3.1)
|
||||
* @bytes_recvd: Number of bytes received since last sending feedback
|
||||
*/
|
||||
struct tfrc_rx_hist {
|
||||
struct tfrc_rx_hist_entry *ring[TFRC_NDUPACK + 1];
|
||||
u8 loss_count:2,
|
||||
loss_start:2;
|
||||
#define rtt_sample_prev loss_start
|
||||
u32 packet_size,
|
||||
bytes_recvd;
|
||||
};
|
||||
|
||||
/**
|
||||
|
@ -140,6 +144,18 @@ static inline bool tfrc_rx_hist_loss_pending(const struct tfrc_rx_hist *h)
|
|||
return h->loss_count > 0;
|
||||
}
|
||||
|
||||
/*
|
||||
* Accessor functions to retrieve parameters sampled by the RX history
|
||||
*/
|
||||
static inline u32 tfrc_rx_hist_packet_size(const struct tfrc_rx_hist *h)
|
||||
{
|
||||
if (h->packet_size == 0) {
|
||||
DCCP_WARN("No sample for s, using fallback\n");
|
||||
return TCP_MIN_RCVMSS;
|
||||
}
|
||||
return h->packet_size;
|
||||
}
|
||||
|
||||
extern void tfrc_rx_hist_add_packet(struct tfrc_rx_hist *h,
|
||||
const struct sk_buff *skb, const u64 ndp);
|
||||
|
||||
|
|
|
@ -185,7 +185,7 @@ int dccp_init_sock(struct sock *sk, const __u8 ctl_sock_initialized)
|
|||
sk->sk_state = DCCP_CLOSED;
|
||||
sk->sk_write_space = dccp_write_space;
|
||||
icsk->icsk_sync_mss = dccp_sync_mss;
|
||||
dp->dccps_mss_cache = 536;
|
||||
dp->dccps_mss_cache = TCP_MIN_RCVMSS;
|
||||
dp->dccps_rate_last = jiffies;
|
||||
dp->dccps_role = DCCP_ROLE_UNDEFINED;
|
||||
dp->dccps_service = DCCP_SERVICE_CODE_IS_ABSENT;
|
||||
|
|
Loading…
Reference in a new issue