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/linux/Documentation/devicetree/bindings/rtc/
H A Datmel,at91sam9260-rtt.yaml5 $id: http://devicetree.org/schemas/rtc/atmel,at91sam9260-rtt.yaml#
8 title: Atmel AT91 RTT
20 - const: atmel,at91sam9260-rtt
23 - microchip,sam9x60-rtt
24 - microchip,sam9x7-rtt
25 - const: atmel,at91sam9260-rtt
27 - const: microchip,sama7g5-rtt
28 - const: microchip,sam9x60-rtt
29 - const: atmel,at91sam9260-rtt
40 atmel,rtt-rtc-time-reg:
[all …]
/linux/net/ipv4/
H A Dtcp_vegas.c19 * only every-other RTT during slow start, we increase during
20 * every RTT during slow start, just like Reno.
27 * minimum RTT sample observed during the last RTT to calculate
64 * end of the first RTT, because any calculation we do is using
68 * Instead we must wait until the completion of an RTT during
103 /* Do RTT sampling needed for Vegas.
105 * o min-filter RTT samples from within an RTT to get the current
108 * o min-filter RTT samples from a much longer window (forever for now)
119 /* Never allow zero rtt or baseRTT */ in tcp_vegas_pkts_acked()
126 /* Find the min RTT during the last RTT to find in tcp_vegas_pkts_acked()
[all …]
H A Dtcp_yeah.c20 #define TCP_YEAH_GAMMA 1 /* fraction of queue to be removed per rtt */
24 #define TCP_YEAH_RHO 16 /* minimum number of consecutive rtt to consider competition on los…
84 * of snd_una and snd_nxt at the beginning of the current RTT. More in tcp_yeah_cong_avoid()
85 * precisely, they represent the amount of data sent during the RTT. in tcp_yeah_cong_avoid()
86 * At the end of the RTT, when we receive an ACK for v_beg_snd_nxt, in tcp_yeah_cong_avoid()
88 * bytes of data have been ACKed during the course of the RTT, giving in tcp_yeah_cong_avoid()
91 * (v_beg_snd_nxt - v_vegas.beg_snd_una) / (rtt duration) in tcp_yeah_cong_avoid()
99 * of bytes we send in an RTT is often less than our cwnd will allow. in tcp_yeah_cong_avoid()
104 /* We do the Vegas calculations only if we got enough RTT in tcp_yeah_cong_avoid()
106 * at least one RTT sample that wasn't from a delayed ACK. in tcp_yeah_cong_avoid()
[all …]
H A Dtcp_veno.c28 u8 doing_veno_now; /* if true, do veno for this rtt */
29 u16 cntrtt; /* # of rtts measured within last rtt */
30 u32 minrtt; /* min of rtts measured within last rtt (in usec) */
31 u32 basertt; /* the min of all Veno rtt measurements seen (in usec) */
72 /* Do rtt sampling needed for Veno. */
82 /* Never allow zero rtt or baseRTT */ in tcp_veno_pkts_acked()
89 /* Find the min rtt during the last rtt to find in tcp_veno_pkts_acked()
107 * until we get fresh rtt samples. So when we
133 /* We do the Veno calculations only if we got enough rtt samples */ in tcp_veno_cong_avoid()
135 /* We don't have enough rtt samples to do the Veno in tcp_veno_cong_avoid()
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H A Dtcp_westwood.c40 u32 rtt; member
41 u32 rtt_min; /* minimum observed RTT */
43 u8 reset_rtt_min; /* Reset RTT min to next RTT sample*/
59 * RTT period of the connection lifetime.
71 w->rtt_min = w->rtt = TCP_WESTWOOD_INIT_RTT; in tcp_westwood_init()
109 w->rtt = usecs_to_jiffies(sample->rtt_us); in tcp_westwood_pkts_acked()
114 * It updates RTT evaluation window if it is the right moment to do
132 * See if a RTT-window has passed. in westwood_update_window()
133 * Be careful since if RTT is less than in westwood_update_window()
140 if (w->rtt && delta > max_t(u32, w->rtt, TCP_WESTWOOD_RTT_MIN)) { in westwood_update_window()
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H A Dtcp_nv.c21 * due to the increased noise in RTT values. In particular, we have
41 * nv_rtt_factor RTT averaging factor
43 * nv_dec_eval_min_calls Wait this many RTT measurements before dec cwnd
44 * nv_inc_eval_min_calls Wait this many RTT measurements before inc cwnd
45 * nv_ssthresh_eval_min_calls Wait this many RTT measurements before stopping
53 * rate < 1 pkt/RTT (after losses). The other (nv_cwnd_growth_rate_pos)
86 * < 0 => less than 1 packet/RTT */
101 u32 nv_last_rtt; /* last rtt */
102 u32 nv_min_rtt; /* active min rtt. Used to determine slope */
103 u32 nv_min_rtt_new; /* min rtt for future use */
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H A Dtcp_vegas.h10 u32 beg_snd_nxt; /* right edge during last RTT */
11 u32 beg_snd_una; /* left edge during last RTT */
13 u8 doing_vegas_now;/* if true, do vegas for this RTT */
14 u16 cntRTT; /* # of RTTs measured within last RTT */
15 u32 minRTT; /* min of RTTs measured within last RTT (in usec) */
16 u32 baseRTT; /* the min of all Vegas RTT measurements seen (in usec) */
H A Dtcp_illinois.c41 MODULE_PARM_DESC(theta, "# of fast RTT's before full growth");
45 u64 sum_rtt; /* sum of rtt's measured within last rtt */
46 u16 cnt_rtt; /* # of rtts measured within last rtt */
47 u32 base_rtt; /* min of all rtt in usec */
48 u32 max_rtt; /* max of all rtt in usec */
49 u32 end_seq; /* right edge of current RTT */
53 u8 rtt_above; /* average rtt has gone above threshold */
85 /* Measure RTT for each ack. */
93 /* dup ack, no rtt sample */ in tcp_illinois_acked()
101 /* keep track of minimum RTT seen so far */ in tcp_illinois_acked()
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H A Dtcp_cdg.c80 struct cdg_minmax rtt; member
145 ca->delay_min = min_not_zero(ca->delay_min, ca->rtt.min); in tcp_cdg_hystart_update()
178 if (ca->rtt.min > thresh) { in tcp_cdg_hystart_update()
192 s32 gmin = ca->rtt.min - ca->rtt_prev.min; in tcp_cdg_grad()
193 s32 gmax = ca->rtt.max - ca->rtt_prev.max; in tcp_cdg_grad()
272 if (after(ack, ca->rtt_seq) && ca->rtt.v64) { in tcp_cdg_cong_avoid()
278 ca->rtt_prev = ca->rtt; in tcp_cdg_cong_avoid()
279 ca->rtt.v64 = 0; in tcp_cdg_cong_avoid()
316 ca->rtt.min = min(ca->rtt.min, sample->rtt_us); in tcp_cdg_acked()
324 ca->rtt.min = min_not_zero(ca->rtt.min, sample->rtt_us); in tcp_cdg_acked()
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H A Dtcp_recovery.c23 * Use min_rtt instead of the smoothed RTT because reordering is in tcp_rack_reo_wnd()
26 * smoothed RTT. in tcp_rack_reo_wnd()
82 * the recent RTT plus the reordering window. in tcp_rack_detect_loss()
115 * This is "Step 3: Advance RACK.xmit_time and update RACK.RTT" from
132 * so it's at least one RTT (i.e., retransmission is at least in tcp_rack_advance()
133 * an RTT later). in tcp_rack_advance()
180 * At max, reo_wnd is incremented only once per rtt. So that the new
185 * absolute value to account for change in rtt.
196 /* Disregard DSACK if a rtt has not passed since we adjusted reo_wnd */ in tcp_rack_update_reo_wnd()
H A Dtcp_metrics.c37 * Kernel only stores RTT and RTTVAR in usec resolution
347 unsigned long rtt; in tcp_update_metrics() local
357 /* This session failed to estimate rtt. Why? in tcp_update_metrics()
371 rtt = tcp_metric_get(tm, TCP_METRIC_RTT); in tcp_update_metrics()
372 m = rtt - tp->srtt_us; in tcp_update_metrics()
374 /* If newly calculated rtt larger than stored one, store new in tcp_update_metrics()
375 * one. Otherwise, use EWMA. Remember, rtt overestimation is in tcp_update_metrics()
380 rtt = tp->srtt_us; in tcp_update_metrics()
382 rtt -= (m >> 3); in tcp_update_metrics()
383 tcp_metric_set(tm, TCP_METRIC_RTT, rtt); in tcp_update_metrics()
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H A Dtcp_cubic.c104 u32 curr_rtt; /* the minimum rtt of current round */
254 /* calculate c * time^3 / rtt, in bictcp_update()
262 * rtt = (srtt >> 3) / HZ in bictcp_update()
278 /* c/rtt * (t-K)^3 */ in bictcp_update()
297 ca->cnt = 20; /* increase cwnd 5% per RTT */ in bictcp_update()
319 * 2 packets ACKed, meaning cwnd grows at 1.5x per RTT. in bictcp_update()
367 * Otherwise short RTT flows could get too small ssthresh, since during
370 * Ideally even with a very small RTT we would like to have at least one
406 * Pacing might have delayed packets up to RTT/2 in hystart_update()
515 cube_rtt_scale = (bic_scale * 10); /* 1024*c/rtt */ in cubictcp_register()
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H A Dtcp_lp.c17 * OWD have a similar meaning as RTT. Also correct the buggy formular.
186 * difference directly. As this time difference just simply equal to RTT, when
187 * the network status is stable, remote RTT will equal to local RTT, and result
217 * @sk: socket to add a rtt sample to
218 * @rtt: round trip time, which is ignored!
227 static void tcp_lp_rtt_sample(struct sock *sk, u32 rtt) in tcp_lp_rtt_sample() argument
/linux/net/rxrpc/
H A Drtt.c2 /* RTT/RTO calculation.
34 * Called to compute a smoothed rtt estimate. The data fed to this
45 long m = sample_rtt_us; /* RTT */ in rxrpc_rtt_estimator()
49 * article in SIGCOMM '88. Note that rtt and mdev in rxrpc_rtt_estimator()
50 * are scaled versions of rtt and mean deviation. in rxrpc_rtt_estimator()
55 * RTO = rtt + 4 * mdev in rxrpc_rtt_estimator()
65 m -= (srtt >> 3); /* m is now error in rtt est */ in rxrpc_rtt_estimator()
66 srtt += m; /* rtt = 7/8 rtt + 1/8 new */ in rxrpc_rtt_estimator()
71 * Eifel blocks mdev updates when rtt decreases. in rxrpc_rtt_estimator()
92 srtt = m << 3; /* take the measured time to be rtt */ in rxrpc_rtt_estimator()
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/linux/tools/testing/selftests/tc-testing/tc-tests/qdiscs/
H A Dcake.json17 …th unlimited diffserv3 triple-isolate nonat nowash no-ack-filter split-gso rtt 100ms raw overhead",
38 …dwidth 1Kbit diffserv3 triple-isolate nonat nowash no-ack-filter split-gso rtt 100ms raw overhead",
59 …rate-ingress diffserv3 triple-isolate nonat nowash no-ack-filter split-gso rtt 100ms raw overhead",
67 "name": "Create CAKE with rtt time",
77 "cmdUnderTest": "$TC qdisc add dev $DUMMY handle 1: root cake rtt 200",
80 …th unlimited diffserv3 triple-isolate nonat nowash no-ack-filter split-gso rtt 200us raw overhead",
101 …h unlimited besteffort triple-isolate nonat nowash no-ack-filter split-gso rtt 100ms raw overhead",
122 …th unlimited diffserv8 triple-isolate nonat nowash no-ack-filter split-gso rtt 100ms raw overhead",
143 …th unlimited diffserv4 triple-isolate nonat nowash no-ack-filter split-gso rtt 100ms raw overhead",
164 …ndwidth unlimited diffserv3 flowblind nonat nowash no-ack-filter split-gso rtt 100ms raw overhead",
[all …]
/linux/Documentation/netlink/specs/
H A Dtcp_metrics.yaml89 are off-by one (e.g. rtt is defined as enum 0, while netlink carries
93 name: rtt
96 Round Trip Time (RTT), in msecs with 3 bits fractional
102 Round Trip Time VARiance (RTT), in msecs with 2 bits fractional
117 name: rtt-us
120 Round Trip Time (RTT), in usecs, with 3 bits fractional
126 Round Trip Time (RTT), in usecs, with 2 bits fractional
/linux/fs/afs/
H A Dvl_probe.c21 server->rtt = UINT_MAX; in afs_finished_vl_probe()
120 if (rtt_us < server->probe.rtt) { in afs_vlserver_probe_result()
121 server->probe.rtt = rtt_us; in afs_vlserver_probe_result()
122 server->rtt = rtt_us; in afs_vlserver_probe_result()
126 smp_wmb(); /* Set rtt before responded. */ in afs_vlserver_probe_result()
135 _debug("probe [%u][%u] %pISpc rtt=%d ret=%d", in afs_vlserver_probe_result()
169 server->probe.rtt = UINT_MAX; in afs_do_probe_vlserver()
233 unsigned int rtt = UINT_MAX, rtt_s; in afs_wait_for_vl_probes() local
289 rtt_s = READ_ONCE(server->rtt); in afs_wait_for_vl_probes()
291 rtt_s < rtt) { in afs_wait_for_vl_probes()
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/linux/net/sunrpc/
H A Dtimer.c12 * This RTT estimator is used only for RPC over datagram protocols.
30 * rpc_init_rtt - Initialize an RPC RTT estimator context
53 * rpc_update_rtt - Update an RPC RTT estimator context
56 * @m: recent actual RTT, in jiffies
58 * NB: When computing the smoothed RTT and standard deviation,
98 * the mean and mean deviation of RTT for the appropriate type of RPC
/linux/drivers/rtc/
H A Drtc-at91sam9.c3 * "RTT as Real Time Clock" driver for AT91SAM9 SoC family
30 * - A "Real-time Timer" (RTT) counts up in seconds from a base time.
38 * The RTC's value is the RTT counter plus that offset. The RTC's alarm
69 void __iomem *rtt; member
82 readl((rtc)->rtt + AT91_RTT_ ## field)
84 writel((val), (rtc)->rtt + AT91_RTT_ ## field)
360 rtc->rtt = devm_platform_ioremap_resource(pdev, 0); in at91_rtc_probe()
361 if (IS_ERR(rtc->rtt)) in at91_rtc_probe()
362 return PTR_ERR(rtc->rtt); in at91_rtc_probe()
365 "atmel,rtt-rtc-time-reg", 1, 0, in at91_rtc_probe()
[all …]
/linux/tools/testing/selftests/bpf/progs/
H A Dbpf_cubic.c60 static const __u32 cube_rtt_scale = (bic_scale * 10); /* 1024*c/rtt */
63 /* calculate the "K" for (wmax-cwnd) = c/rtt * K^3
64 * so K = cubic_root( (wmax-cwnd)*rtt/c )
68 * rtt = 100ms
72 * RTT < 100 seconds
99 __u32 curr_rtt; /* the minimum rtt of current round */
312 /* calculate c * time^3 / rtt, in bictcp_update()
320 * rtt = (srtt >> 3) / HZ in bictcp_update()
336 /* c/rtt * (t-K)^3 */ in bictcp_update()
355 ca->cnt = 20; /* increase cwnd 5% per RTT */ in bictcp_update()
[all …]
/linux/net/dccp/ccids/
H A Dccid3.c66 * X_init = min(4 * s, max(2 * s, 4380 bytes)) / RTT
124 * a sender is idle if it has not sent anything over a 2-RTT-period. in ccid3_hc_tx_update_x()
174 * As elsewhere, RTT > 0 is assumed by using dccp_sample_rtt().
299 * Use initial RTT sample when available: recommended by erratum in ccid3_hc_tx_send_packet()
304 ccid3_pr_debug("SYN RTT = %uus\n", dp->dccps_syn_rtt); in ccid3_hc_tx_send_packet()
310 * Sender does not have RTT sample: in ccid3_hc_tx_send_packet()
311 * - set fallback RTT (RFC 4340, 3.4) since a RTT value in ccid3_hc_tx_send_packet()
382 /* For the sake of RTT sampling, ignore/remove all older entries */ in ccid3_hc_tx_packet_recv()
385 /* Update the moving average for the RTT estimate (RFC 3448, 4.3) */ in ccid3_hc_tx_packet_recv()
420 ccid3_pr_debug("%s(%p), RTT=%uus (sample=%uus), s=%u, " in ccid3_hc_tx_packet_recv()
[all …]
/linux/samples/bpf/
H A Dhbm_kern.h75 int rtt; member
95 pkti->rtt = tp->srtt_us >> 3; in get_tcp_info()
103 pkti->rtt = 0; in get_tcp_info()
115 pkti->rtt = 0; in hbm_get_pkt_info()
192 if (pkti->rtt) in hbm_update_stats()
194 pkti->rtt); in hbm_update_stats()
/linux/Documentation/driver-api/nvdimm/
H A Dbtt.rst169 d. In-memory data structure: Read Tracking Table (RTT)
181 incorrect data. To prevent this, we introduce the RTT.
183 The RTT is a simple, per arena table with 'nfree' entries. Every reader inserts
184 into rtt[lane_number], the postmap ABA it is reading, and clears it after the
186 RTT for its presence. If the postmap free block is in the RTT, it waits till the
187 reader clears the RTT entry, and only then starts writing to it.
231 4. Enter post-map ABA into RTT[lane]
235 8. Remove post-map ABA entry from RTT[lane]
244 4. Scan the RTT to check if free block is present, and spin/wait if it is.
/linux/net/sctp/
H A Dtransport.c54 * C1) Until an RTT measurement has been made for a packet sent to the in sctp_transport_init()
487 /* Update transport's RTO based on the newly calculated RTT. */
488 void sctp_transport_update_rto(struct sctp_transport *tp, __u32 rtt) in sctp_transport_update_rto() argument
496 /* 6.3.1 C3) When a new RTT measurement R' is made, set in sctp_transport_update_rto()
508 + (((__u32)abs((__s64)tp->srtt - (__s64)rtt)) >> net->sctp.rto_beta); in sctp_transport_update_rto()
510 + (rtt >> net->sctp.rto_alpha); in sctp_transport_update_rto()
512 /* 6.3.1 C2) When the first RTT measurement R is made, set in sctp_transport_update_rto()
515 tp->srtt = rtt; in sctp_transport_update_rto()
516 tp->rttvar = rtt >> 1; in sctp_transport_update_rto()
541 tp->rtt = rtt; in sctp_transport_update_rto()
[all …]
/linux/net/ax25/
H A Dax25_subr.c239 ax25->t1 = t * ax25->rtt; in ax25_calculate_t1()
251 ax25->rtt = (9 * ax25->rtt + ax25->t1 - ax25_display_timer(&ax25->t1timer)) / 10; in ax25_calculate_rtt()
253 if (ax25->rtt < AX25_T1CLAMPLO) in ax25_calculate_rtt()
254 ax25->rtt = AX25_T1CLAMPLO; in ax25_calculate_rtt()
256 if (ax25->rtt > AX25_T1CLAMPHI) in ax25_calculate_rtt()
257 ax25->rtt = AX25_T1CLAMPHI; in ax25_calculate_rtt()

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