From b6ee3d4ada4e85d9b9b9164c1327ef0850c79d5e Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Sat, 27 Aug 2005 18:18:18 -0300 Subject: [PATCH] [CCID3]: Reorganise timeval handling Introducing functions to add to or subtract from a timeval variable and renaming now_delta to timeval_new_delta that calls do_gettimeofday and then timeval_delta, that should be used when there are several deltas made relative to the current time or setting variables to it, so as to avoid calling do_gettimeofday excessively. I'm leaving these "timeval_" prefixed funcions internal to DCCP for a while till we're sure there are no subtle bugs in it. It also is more correct as it checks if the number of usecs added to or subtracted from a tv_usec field is more than 2 seconds. Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: David S. Miller --- net/dccp/ccids/ccid3.c | 127 +++++++++++++++++++++---------------------------- net/dccp/dccp.h | 44 +++++++++++++++-- net/dccp/options.c | 5 +- 3 files changed, 98 insertions(+), 78 deletions(-) diff --git a/net/dccp/ccids/ccid3.c b/net/dccp/ccids/ccid3.c index 225c530..60e3a5f 100644 --- a/net/dccp/ccids/ccid3.c +++ b/net/dccp/ccids/ccid3.c @@ -156,26 +156,6 @@ static inline void ccid3_hc_tx_set_state(struct sock *sk, hctx->ccid3hctx_state = state; } -static void timeval_sub(struct timeval large, struct timeval small, - struct timeval *result) -{ - result->tv_sec = large.tv_sec-small.tv_sec; - if (large.tv_usec < small.tv_usec) { - (result->tv_sec)--; - result->tv_usec = USEC_PER_SEC + - large.tv_usec - small.tv_usec; - } else - result->tv_usec = large.tv_usec-small.tv_usec; -} - -static inline void timeval_fix(struct timeval *tv) -{ - if (tv->tv_usec >= USEC_PER_SEC) { - tv->tv_sec++; - tv->tv_usec -= USEC_PER_SEC; - } -} - #define CALCX_ARRSIZE 500 #define CALCX_SPLIT 50000 @@ -816,18 +796,22 @@ static void ccid3_hc_tx_update_x(struct sock *sk) 2 * hctx->ccid3hctx_x_recv), (hctx->ccid3hctx_s / TFRC_MAX_BACK_OFF_TIME)); - } else if (now_delta(hctx->ccid3hctx_t_ld) >= hctx->ccid3hctx_rtt) { - u32 rtt = hctx->ccid3hctx_rtt; - if (rtt < 10) { - rtt = 10; - } /* avoid divide by zero below */ - - hctx->ccid3hctx_x = max_t(u32, min_t(u32, 2 * hctx->ccid3hctx_x_recv, - 2 * hctx->ccid3hctx_x), - ((hctx->ccid3hctx_s * 100000) / - (rtt / 10))); - /* Using 100000 and 10 to avoid 32 bit overflow for jumbo frames */ - do_gettimeofday(&hctx->ccid3hctx_t_ld); + } else { + struct timeval now; + + do_gettimeofday(&now); + if (timeval_delta(&now, &hctx->ccid3hctx_t_ld) >= + hctx->ccid3hctx_rtt) { + /* Avoid divide by zero below */ + const u32 rtt = max_t(u32, hctx->ccid3hctx_rtt, 10); + + hctx->ccid3hctx_x = max_t(u32, min_t(u32, 2 * hctx->ccid3hctx_x_recv, + 2 * hctx->ccid3hctx_x), + ((hctx->ccid3hctx_s * 100000) / + (rtt / 10))); + /* Using 100000 and 10 to avoid 32 bit overflow for jumbo frames */ + hctx->ccid3hctx_t_ld = now; + } } if (hctx->ccid3hctx_x == 0) { @@ -999,14 +983,15 @@ static int ccid3_hc_tx_send_packet(struct sock *sk, /* Set nominal send time for initial packet */ hctx->ccid3hctx_t_nom = now; - (hctx->ccid3hctx_t_nom).tv_usec += hctx->ccid3hctx_t_ipi; - timeval_fix(&(hctx->ccid3hctx_t_nom)); + timeval_add_usecs(&hctx->ccid3hctx_t_nom, + hctx->ccid3hctx_t_ipi); ccid3_calc_new_delta(hctx); rc = 0; break; case TFRC_SSTATE_NO_FBACK: case TFRC_SSTATE_FBACK: - delay = now_delta(hctx->ccid3hctx_t_nom) - hctx->ccid3hctx_delta; + delay = (timeval_delta(&now, &hctx->ccid3hctx_t_nom) - + hctx->ccid3hctx_delta); ccid3_pr_debug("send_packet delay=%ld\n", delay); delay /= -1000; /* divide by -1000 is to convert to ms and get sign right */ @@ -1068,7 +1053,7 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len) * Algorithm in "8.1. Window Counter Valuer" in * draft-ietf-dccp-ccid3-11.txt */ - quarter_rtt = now_delta(hctx->ccid3hctx_t_last_win_count) / + quarter_rtt = timeval_delta(&now, &hctx->ccid3hctx_t_last_win_count) / (hctx->ccid3hctx_rtt / 4); if (quarter_rtt > 0) { hctx->ccid3hctx_t_last_win_count = now; @@ -1102,8 +1087,8 @@ static void ccid3_hc_tx_packet_sent(struct sock *sk, int more, int len) hctx->ccid3hctx_t_nom = now; ccid3_calc_new_t_ipi(hctx); ccid3_calc_new_delta(hctx); - (hctx->ccid3hctx_t_nom).tv_usec += hctx->ccid3hctx_t_ipi; - timeval_fix(&(hctx->ccid3hctx_t_nom)); + timeval_add_usecs(&hctx->ccid3hctx_t_nom, + hctx->ccid3hctx_t_ipi); } break; default: @@ -1167,7 +1152,7 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) } /* Update RTT */ - r_sample = now_delta(packet->dccphtx_tstamp); + r_sample = timeval_now_delta(&packet->dccphtx_tstamp); /* FIXME: */ // r_sample -= usecs_to_jiffies(t_elapsed * 10); @@ -1224,15 +1209,11 @@ static void ccid3_hc_tx_packet_recv(struct sock *sk, struct sk_buff *skb) ccid3_hc_tx_update_x(sk); /* Update next send time */ - if (hctx->ccid3hctx_t_ipi > (hctx->ccid3hctx_t_nom).tv_usec) { - hctx->ccid3hctx_t_nom.tv_usec += USEC_PER_SEC; - (hctx->ccid3hctx_t_nom).tv_sec--; - } - /* FIXME - if no feedback then t_ipi can go > 1 second */ - (hctx->ccid3hctx_t_nom).tv_usec -= hctx->ccid3hctx_t_ipi; + timeval_sub_usecs(&hctx->ccid3hctx_t_nom, + hctx->ccid3hctx_t_ipi); ccid3_calc_new_t_ipi(hctx); - (hctx->ccid3hctx_t_nom).tv_usec += hctx->ccid3hctx_t_ipi; - timeval_fix(&(hctx->ccid3hctx_t_nom)); + timeval_add_usecs(&hctx->ccid3hctx_t_nom, + hctx->ccid3hctx_t_ipi); ccid3_calc_new_delta(hctx); /* remove all packets older than the one acked from history */ @@ -1559,20 +1540,24 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk) struct dccp_sock *dp = dccp_sk(sk); struct ccid3_hc_rx_sock *hcrx = dp->dccps_hc_rx_ccid_private; struct dccp_rx_hist_entry *packet; + struct timeval now; ccid3_pr_debug("%s, sk=%p\n", dccp_role(sk), sk); + do_gettimeofday(&now); + switch (hcrx->ccid3hcrx_state) { case TFRC_RSTATE_NO_DATA: hcrx->ccid3hcrx_x_recv = 0; break; case TFRC_RSTATE_DATA: { - u32 delta = now_delta(hcrx->ccid3hcrx_tstamp_last_feedback); + const u32 delta = timeval_delta(&now, + &hcrx->ccid3hcrx_tstamp_last_feedback); - if (delta == 0) - delta = 1; /* to prevent divide by zero */ hcrx->ccid3hcrx_x_recv = (hcrx->ccid3hcrx_bytes_recv * - USEC_PER_SEC) / delta; + USEC_PER_SEC); + if (likely(delta > 1)) + hcrx->ccid3hcrx_x_recv /= delta; } break; default: @@ -1590,13 +1575,14 @@ static void ccid3_hc_rx_send_feedback(struct sock *sk) return; } - do_gettimeofday(&(hcrx->ccid3hcrx_tstamp_last_feedback)); + hcrx->ccid3hcrx_tstamp_last_feedback = now; hcrx->ccid3hcrx_last_counter = packet->dccphrx_ccval; hcrx->ccid3hcrx_seqno_last_counter = packet->dccphrx_seqno; hcrx->ccid3hcrx_bytes_recv = 0; /* Convert to multiples of 10us */ - hcrx->ccid3hcrx_elapsed_time = now_delta(packet->dccphrx_tstamp) / 10; + hcrx->ccid3hcrx_elapsed_time = + timeval_delta(&now, &packet->dccphrx_tstamp) / 10; if (hcrx->ccid3hcrx_p == 0) hcrx->ccid3hcrx_pinv = ~0; else @@ -1676,7 +1662,7 @@ static u32 ccid3_hc_rx_calc_first_li(struct sock *sk) struct ccid3_hc_rx_sock *hcrx = dp->dccps_hc_rx_ccid_private; struct dccp_rx_hist_entry *entry, *next, *tail = NULL; u32 rtt, delta, x_recv, fval, p, tmp2; - struct timeval tstamp = { 0 }, tmp_tv; + struct timeval tstamp = { 0, }; int interval = 0; int win_count = 0; int step = 0; @@ -1718,18 +1704,16 @@ static u32 ccid3_hc_rx_calc_first_li(struct sock *sk) interval = 1; } found: - timeval_sub(tstamp,tail->dccphrx_tstamp,&tmp_tv); - rtt = (tmp_tv.tv_sec * USEC_PER_SEC + tmp_tv.tv_usec) * 4 / interval; + rtt = timeval_delta(&tstamp, &tail->dccphrx_tstamp) * 4 / interval; ccid3_pr_debug("%s, sk=%p, approximated RTT to %uus\n", dccp_role(sk), sk, rtt); if (rtt == 0) rtt = 1; - delta = now_delta(hcrx->ccid3hcrx_tstamp_last_feedback); - if (delta == 0) - delta = 1; - - x_recv = (hcrx->ccid3hcrx_bytes_recv * USEC_PER_SEC) / delta; + delta = timeval_now_delta(&hcrx->ccid3hcrx_tstamp_last_feedback); + x_recv = hcrx->ccid3hcrx_bytes_recv * USEC_PER_SEC; + if (likely(delta > 1)) + x_recv /= delta; tmp1 = (u64)x_recv * (u64)rtt; do_div(tmp1,10000000); @@ -1926,7 +1910,6 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) const struct dccp_options_received *opt_recv; struct dccp_rx_hist_entry *packet; struct timeval now; - u32 now_usecs; u8 win_count; u32 p_prev; int ins; @@ -1948,8 +1931,7 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) break; p_prev = hcrx->ccid3hcrx_rtt; do_gettimeofday(&now); - now_usecs = now.tv_sec * USEC_PER_SEC + now.tv_usec; - hcrx->ccid3hcrx_rtt = now_usecs - + hcrx->ccid3hcrx_rtt = timeval_usecs(&now) - (opt_recv->dccpor_timestamp_echo - opt_recv->dccpor_elapsed_time) * 10; if (p_prev != hcrx->ccid3hcrx_rtt) @@ -1994,15 +1976,16 @@ static void ccid3_hc_rx_packet_recv(struct sock *sk, struct sk_buff *skb) case TFRC_RSTATE_DATA: hcrx->ccid3hcrx_bytes_recv += skb->len - dccp_hdr(skb)->dccph_doff * 4; - if (ins == 0) { - if (now_delta(hcrx->ccid3hcrx_tstamp_last_ack) >= - hcrx->ccid3hcrx_rtt) { - do_gettimeofday(&hcrx->ccid3hcrx_tstamp_last_ack); - ccid3_hc_rx_send_feedback(sk); - } - return; + if (ins != 0) + break; + + do_gettimeofday(&now); + if (timeval_delta(&now, &hcrx->ccid3hcrx_tstamp_last_ack) >= + hcrx->ccid3hcrx_rtt) { + hcrx->ccid3hcrx_tstamp_last_ack = now; + ccid3_hc_rx_send_feedback(sk); } - break; + return; default: printk(KERN_CRIT "%s: %s, sk=%p, Illegal state (%d)!\n", __FUNCTION__, dccp_role(sk), sk, hcrx->ccid3hcrx_state); diff --git a/net/dccp/dccp.h b/net/dccp/dccp.h index 6ba2150..5cd9e79 100644 --- a/net/dccp/dccp.h +++ b/net/dccp/dccp.h @@ -429,17 +429,53 @@ extern int dccp_ackpkts_add(struct dccp_ackpkts *ap, u64 ackno, u8 state); extern void dccp_ackpkts_check_rcv_ackno(struct dccp_ackpkts *ap, struct sock *sk, u64 ackno); +static inline suseconds_t timeval_usecs(const struct timeval *tv) +{ + return tv->tv_sec * USEC_PER_SEC + tv->tv_usec; +} + +static inline suseconds_t timeval_delta(const struct timeval *large, + const struct timeval *small) +{ + time_t secs = large->tv_sec - small->tv_sec; + suseconds_t usecs = large->tv_usec - small->tv_usec; + + if (usecs < 0) { + secs--; + usecs += USEC_PER_SEC; + } + return secs * USEC_PER_SEC + usecs; +} + +static inline void timeval_add_usecs(struct timeval *tv, + const suseconds_t usecs) +{ + tv->tv_usec += usecs; + while (tv->tv_usec >= USEC_PER_SEC) { + tv->tv_sec++; + tv->tv_usec -= USEC_PER_SEC; + } +} + +static inline void timeval_sub_usecs(struct timeval *tv, + const suseconds_t usecs) +{ + tv->tv_usec -= usecs; + while (tv->tv_usec < 0) { + tv->tv_sec--; + tv->tv_usec += USEC_PER_SEC; + } +} + /* * Returns the difference in usecs between timeval * passed in and current time */ -static inline u32 now_delta(struct timeval tv) +static inline suseconds_t timeval_now_delta(const struct timeval *tv) { struct timeval now; - do_gettimeofday(&now); - return (now.tv_sec - tv.tv_sec) * USEC_PER_SEC + - (now.tv_usec - tv.tv_usec); + return timeval_delta(&now, tv); } #ifdef CONFIG_IP_DCCP_DEBUG diff --git a/net/dccp/options.c b/net/dccp/options.c index eabcc8f..382c589 100644 --- a/net/dccp/options.c +++ b/net/dccp/options.c @@ -359,7 +359,7 @@ static void dccp_insert_option_ack_vector(struct sock *sk, struct sk_buff *skb) #endif struct dccp_ackpkts *ap = dp->dccps_hc_rx_ackpkts; int len = ap->dccpap_buf_vector_len + 2; - const u32 elapsed_time = now_delta(ap->dccpap_time) / 10; + const u32 elapsed_time = timeval_now_delta(&ap->dccpap_time) / 10; unsigned char *to, *from; if (elapsed_time != 0) @@ -451,7 +451,8 @@ static void dccp_insert_option_timestamp_echo(struct sock *sk, "CLIENT TX opt: " : "server TX opt: "; #endif u32 tstamp_echo; - const u32 elapsed_time = now_delta(dp->dccps_timestamp_time) / 10; + const u32 elapsed_time = + timeval_now_delta(&dp->dccps_timestamp_time) / 10; const int elapsed_time_len = dccp_elapsed_time_len(elapsed_time); const int len = 6 + elapsed_time_len; unsigned char *to; -- 2.7.4