[DCCP]: Cheaper & smaller timestamping
Currently dccp_timestamp calculates timestamps relative to an offset computed
at initialisation time. This patch reduces the cost of timestamping by
removing
the offset computation. This affords the advantages that
* there are now fewer instructions per single timestamp;
* the size of the dccp_sock becomes smaller (minus @dccps_epoch).
(NB: Using a reference epoch is not strictly necessary, since all known
timestamping
operations in DCCP only need relative time differences, but not absolute
time.
I have tested this patch for a while on different platforms, found no
problems.)
Signed-off-by: Gerrit Renker <[EMAIL PROTECTED]>
---
include/linux/dccp.h | 2 --
net/dccp/ackvec.c | 4 ++--
net/dccp/ccids/ccid3.c | 18 +++++++++---------
net/dccp/ccids/lib/packet_history.h | 2 +-
net/dccp/dccp.h | 2 --
net/dccp/input.c | 2 +-
net/dccp/minisocks.c | 1 -
net/dccp/options.c | 22 +++-------------------
net/dccp/proto.c | 1 -
9 files changed, 16 insertions(+), 38 deletions(-)
--- a/include/linux/dccp.h
+++ b/include/linux/dccp.h
@@ -476,7 +476,6 @@ struct dccp_ackvec;
* @dccps_hc_rx_ccid -
* @dccps_hc_tx_ccid -
* @dccps_options_received -
- * @dccps_epoch -
* @dccps_role - Role of this sock, one of %dccp_role
* @dccps_hc_rx_insert_options -
* @dccps_hc_tx_insert_options -
@@ -512,7 +511,6 @@ struct dccp_sock {
struct ccid *dccps_hc_rx_ccid;
struct ccid *dccps_hc_tx_ccid;
struct dccp_options_received dccps_options_received;
- struct timeval dccps_epoch;
enum dccp_role dccps_role:2;
__u8 dccps_hc_rx_insert_options:1;
__u8 dccps_hc_tx_insert_options:1;
--- a/net/dccp/options.c
+++ b/net/dccp/options.c
@@ -158,7 +158,7 @@ int dccp_parse_options(struct sock *sk,
opt_recv->dccpor_timestamp = ntohl(*(__be32 *)value);
dp->dccps_timestamp_echo = opt_recv->dccpor_timestamp;
- dccp_timestamp(sk, &dp->dccps_timestamp_time);
+ do_gettimeofday(&dp->dccps_timestamp_time);
dccp_pr_debug("%s rx opt: TIMESTAMP=%u, ackno=%llu\n",
dccp_role(sk), opt_recv->dccpor_timestamp,
@@ -370,28 +370,12 @@ int dccp_insert_option_elapsed_time(stru
EXPORT_SYMBOL_GPL(dccp_insert_option_elapsed_time);
-void dccp_timestamp(const struct sock *sk, struct timeval *tv)
-{
- const struct dccp_sock *dp = dccp_sk(sk);
-
- do_gettimeofday(tv);
- tv->tv_sec -= dp->dccps_epoch.tv_sec;
- tv->tv_usec -= dp->dccps_epoch.tv_usec;
-
- while (tv->tv_usec < 0) {
- tv->tv_sec--;
- tv->tv_usec += USEC_PER_SEC;
- }
-}
-
-EXPORT_SYMBOL_GPL(dccp_timestamp);
-
int dccp_insert_option_timestamp(struct sock *sk, struct sk_buff *skb)
{
struct timeval tv;
__be32 now;
- dccp_timestamp(sk, &tv);
+ do_gettimeofday(&tv);
now = htonl(timeval_usecs(&tv) / 10);
/* yes this will overflow but that is the point as we want a
* 10 usec 32 bit timer which mean it wraps every 11.9 hours */
@@ -411,7 +395,7 @@ static int dccp_insert_option_timestamp_
int len, elapsed_time_len;
unsigned char *to;
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
elapsed_time = timeval_delta(&now, &dp->dccps_timestamp_time) / 10;
elapsed_time_len = dccp_elapsed_time_len(elapsed_time);
len = 6 + elapsed_time_len;
--- a/net/dccp/dccp.h
+++ b/net/dccp/dccp.h
@@ -402,8 +402,6 @@ extern int dccp_insert_option(struct soc
unsigned char option,
const void *value, unsigned char len);
-extern void dccp_timestamp(const struct sock *sk, struct timeval *tv);
-
static inline suseconds_t timeval_usecs(const struct timeval *tv)
{
return tv->tv_sec * USEC_PER_SEC + tv->tv_usec;
--- a/net/dccp/ackvec.c
+++ b/net/dccp/ackvec.c
@@ -82,7 +82,7 @@ int dccp_insert_option_ackvec(struct soc
if (DCCP_SKB_CB(skb)->dccpd_opt_len + len > DCCP_MAX_OPT_LEN)
return -1;
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
elapsed_time = timeval_delta(&now, &av->dccpav_time) / 10;
if (elapsed_time != 0 &&
@@ -321,7 +321,7 @@ int dccp_ackvec_add(struct dccp_ackvec *
}
av->dccpav_buf_ackno = ackno;
- dccp_timestamp(sk, &av->dccpav_time);
+ do_gettimeofday(&av->dccpav_time);
out:
return 0;
--- a/net/dccp/ccids/ccid3.c
+++ b/net/dccp/ccids/ccid3.c
@@ -273,7 +273,7 @@ static void ccid3_hc_tx_no_feedback_time
(2 * TFRC_T_MBI));
if (hctx->ccid3hctx_p == 0)
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
} else {
hctx->ccid3hctx_x_recv = hctx->ccid3hctx_x_calc;
hctx->ccid3hctx_x_recv <<= 4;
@@ -325,7 +325,7 @@ static int ccid3_hc_tx_send_packet(struc
if (unlikely(skb->len == 0))
return -EBADMSG;
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
switch (hctx->ccid3hctx_state) {
case TFRC_SSTATE_NO_SENT:
@@ -418,7 +418,7 @@ static void ccid3_hc_tx_packet_sent(stru
}
dccp_tx_hist_add_entry(&hctx->ccid3hctx_hist, packet);
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
packet->dccphtx_tstamp = now;
packet->dccphtx_seqno = dccp_sk(sk)->dccps_gss;
packet->dccphtx_rtt = hctx->ccid3hctx_rtt;
@@ -469,7 +469,7 @@ static void ccid3_hc_tx_packet_recv(stru
else /* can not exceed 100% */
hctx->ccid3hctx_p = 1000000 / pinv;
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
/*
* Calculate new round trip sample as per [RFC 3448, 4.3] by
@@ -751,7 +751,7 @@ static void ccid3_hc_rx_send_feedback(st
ccid3_pr_debug("%s(%p) - entry \n", dccp_role(sk), sk);
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
switch (hcrx->ccid3hcrx_state) {
case TFRC_RSTATE_NO_DATA:
@@ -903,7 +903,7 @@ found:
return ~0;
}
- dccp_timestamp(sk, &tstamp);
+ do_gettimeofday(&tstamp);
delta = timeval_delta(&tstamp, &hcrx->ccid3hcrx_tstamp_last_feedback);
DCCP_BUG_ON(delta <= 0);
@@ -1050,7 +1050,7 @@ static void ccid3_hc_rx_packet_recv(stru
if (opt_recv->dccpor_timestamp_echo == 0)
break;
rtt_prev = hcrx->ccid3hcrx_rtt;
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
r_sample = dccp_sample_rtt(sk, &now, NULL);
if (hcrx->ccid3hcrx_state == TFRC_RSTATE_NO_DATA)
@@ -1099,7 +1099,7 @@ static void ccid3_hc_rx_packet_recv(stru
if (loss)
break;
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
if ((timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) -
(suseconds_t)hcrx->ccid3hcrx_rtt) >= 0) {
hcrx->ccid3hcrx_tstamp_last_ack = now;
@@ -1142,7 +1142,7 @@ static int ccid3_hc_rx_init(struct ccid
hcrx->ccid3hcrx_state = TFRC_RSTATE_NO_DATA;
INIT_LIST_HEAD(&hcrx->ccid3hcrx_hist);
INIT_LIST_HEAD(&hcrx->ccid3hcrx_li_hist);
- dccp_timestamp(sk, &hcrx->ccid3hcrx_tstamp_last_ack);
+ do_gettimeofday(&hcrx->ccid3hcrx_tstamp_last_ack);
hcrx->ccid3hcrx_tstamp_last_feedback = hcrx->ccid3hcrx_tstamp_last_ack;
hcrx->ccid3hcrx_s = 0;
hcrx->ccid3hcrx_rtt = 0;
--- a/net/dccp/ccids/lib/packet_history.h
+++ b/net/dccp/ccids/lib/packet_history.h
@@ -151,7 +151,7 @@ static inline struct dccp_rx_hist_entry
entry->dccphrx_ccval = dh->dccph_ccval;
entry->dccphrx_type = dh->dccph_type;
entry->dccphrx_ndp = ndp;
- dccp_timestamp(sk, &entry->dccphrx_tstamp);
+ do_gettimeofday(&entry->dccphrx_tstamp);
}
return entry;
--- a/net/dccp/minisocks.c
+++ b/net/dccp/minisocks.c
@@ -112,7 +112,6 @@ struct sock *dccp_create_openreq_child(s
newdp->dccps_service_list = NULL;
newdp->dccps_service = dreq->dreq_service;
newicsk->icsk_rto = DCCP_TIMEOUT_INIT;
- do_gettimeofday(&newdp->dccps_epoch);
if (dccp_feat_clone(sk, newsk))
goto out_free;
--- a/net/dccp/proto.c
+++ b/net/dccp/proto.c
@@ -172,7 +172,6 @@ int dccp_init_sock(struct sock *sk, cons
struct inet_connection_sock *icsk = inet_csk(sk);
dccp_minisock_init(&dp->dccps_minisock);
- do_gettimeofday(&dp->dccps_epoch);
/*
* FIXME: We're hardcoding the CCID, and doing this at this point makes
--- a/net/dccp/input.c
+++ b/net/dccp/input.c
@@ -304,7 +304,7 @@ static int dccp_rcv_request_sent_state_p
if (dp->dccps_options_received.dccpor_timestamp_echo) {
struct timeval now;
- dccp_timestamp(sk, &now);
+ do_gettimeofday(&now);
dp->dccps_syn_rtt = dccp_sample_rtt(sk, &now, NULL);
}
-
To unsubscribe from this list: send the line "unsubscribe dccp" in
the body of a message to [EMAIL PROTECTED]
More majordomo info at http://vger.kernel.org/majordomo-info.html
