- 08 7月, 2014 1 次提交
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由 Neal Cardwell 提交于
Always store in snt_synack the time at which the server received the first client SYN and attempted to send the first SYNACK. Recent commit aa27fc50 ("tcp: tcp_v[46]_conn_request: fix snt_synack initialization") resolved an inconsistency between IPv4 and IPv6 in the initialization of snt_synack. This commit brings back the idea from 843f4a55 (tcp: use tcp_v4_send_synack on first SYN-ACK), which was going for the original behavior of snt_synack from the commit where it was added in 9ad7c049 ("tcp: RFC2988bis + taking RTT sample from 3WHS for the passive open side") in v3.1. In addition to being simpler (and probably a tiny bit faster), unconditionally storing the time of the first SYNACK attempt has been useful because it allows calculating a performance metric quantifying how long it took to establish a passive TCP connection. Signed-off-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NYuchung Cheng <ycheng@google.com> Cc: Octavian Purdila <octavian.purdila@intel.com> Cc: Jerry Chu <hkchu@google.com> Acked-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 28 6月, 2014 10 次提交
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由 Octavian Purdila 提交于
Create tcp_conn_request and remove most of the code from tcp_v4_conn_request and tcp_v6_conn_request. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Octavian Purdila 提交于
Add queue_add_hash member to tcp_request_sock_ops so that we can later unify tcp_v4_conn_request and tcp_v6_conn_request. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Octavian Purdila 提交于
Add mss_clamp member to tcp_request_sock_ops so that we can later unify tcp_v4_conn_request and tcp_v6_conn_request. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Octavian Purdila 提交于
Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Octavian Purdila 提交于
Create a new tcp_request_sock_ops method to unify the IPv4/IPv6 signature for tcp_v[46]_send_synack. This allows us to later unify tcp_v4_rtx_synack with tcp_v6_rtx_synack and tcp_v4_conn_request with tcp_v4_conn_request. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Octavian Purdila 提交于
More work in preparation of unifying tcp_v4_conn_request and tcp_v6_conn_request: indirect the init sequence calls via the tcp_request_sock_ops. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Octavian Purdila 提交于
Create wrappers with same signature for the IPv4/IPv6 request routing calls and use these wrappers (via route_req method from tcp_request_sock_ops) in tcp_v4_conn_request and tcp_v6_conn_request with the purpose of unifying the two functions in a later patch. We can later drop the wrapper functions and modify inet_csk_route_req and inet6_cks_route_req to use the same signature. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Octavian Purdila 提交于
Move the specific IPv4/IPv6 cookie sequence initialization to a new method in tcp_request_sock_ops in preparation for unifying tcp_v4_conn_request and tcp_v6_conn_request. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Octavian Purdila 提交于
Move the specific IPv4/IPv6 intializations to a new method in tcp_request_sock_ops in preparation for unifying tcp_v4_conn_request and tcp_v6_conn_request. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Octavian Purdila 提交于
Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 18 6月, 2014 1 次提交
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由 Octavian Purdila 提交于
ir_mark initialization is done for both TCP v4 and v6, move it in the common tcp_openreq_init function. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 11 6月, 2014 1 次提交
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由 Octavian Purdila 提交于
tcp_fragment can be called from process context (from tso_fragment). Add a new gfp parameter to allow it to preserve atomic memory if possible. Signed-off-by: NOctavian Purdila <octavian.purdila@intel.com> Reviewed-by: NChristoph Paasch <christoph.paasch@uclouvain.be> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 23 5月, 2014 1 次提交
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由 Neal Cardwell 提交于
Experience with the recent e114a710 ("tcp: fix cwnd limited checking to improve congestion control") has shown that there are common cases where that commit can cause cwnd to be much larger than necessary. This leads to TSO autosizing cooking skbs that are too large, among other things. The main problems seemed to be: (1) That commit attempted to predict the future behavior of the connection by looking at the write queue (if TSO or TSQ limit sending). That prediction sometimes overestimated future outstanding packets. (2) That commit always allowed cwnd to grow to twice the number of outstanding packets (even in congestion avoidance, where this is not needed). This commit improves both of these, by: (1) Switching to a measurement-based approach where we explicitly track the largest number of packets in flight during the past window ("max_packets_out"), and remember whether we were cwnd-limited at the moment we finished sending that flight. (2) Only allowing cwnd to grow to twice the number of outstanding packets ("max_packets_out") in slow start. In congestion avoidance mode we now only allow cwnd to grow if it was fully utilized. Signed-off-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 14 5月, 2014 3 次提交
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由 Yuchung Cheng 提交于
To avoid large code duplication in IPv6, we need to first simplify the complicate SYN-ACK sending code in tcp_v4_conn_request(). To use tcp_v4(6)_send_synack() to send all SYN-ACKs, we need to initialize the mini socket's receive window before trying to create the child socket and/or building the SYN-ACK packet. So we move that initialization from tcp_make_synack() to tcp_v4_conn_request() as a new function tcp_openreq_init_req_rwin(). After this refactoring the SYN-ACK sending code is simpler and easier to implement Fast Open for IPv6. Signed-off-by: NYuchung Cheng <ycheng@google.com> Signed-off-by: NDaniel Lee <longinus00@gmail.com> Signed-off-by: NJerry Chu <hkchu@google.com> Acked-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Yuchung Cheng 提交于
Consolidate various cookie checking and generation code to simplify the fast open processing. The main goal is to reduce code duplication in tcp_v4_conn_request() for IPv6 support. Removes two experimental sysctl flags TFO_SERVER_ALWAYS and TFO_SERVER_COOKIE_NOT_CHKD used primarily for developmental debugging purposes. Signed-off-by: NYuchung Cheng <ycheng@google.com> Signed-off-by: NDaniel Lee <longinus00@gmail.com> Signed-off-by: NJerry Chu <hkchu@google.com> Signed-off-by: NEric Dumazet <edumazet@google.com> Acked-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Yuchung Cheng 提交于
Move common TFO functions that will be used by both v4 and v6 to tcp_fastopen.c. Create a helper tcp_fastopen_queue_check(). Signed-off-by: NYuchung Cheng <ycheng@google.com> Signed-off-by: NDaniel Lee <longinus00@gmail.com> Signed-off-by: NJerry Chu <hkchu@google.com> Signed-off-by: NEric Dumazet <edumazet@google.com> Acked-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 04 5月, 2014 1 次提交
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由 Eric Dumazet 提交于
Commit e114a710 ("tcp: fix cwnd limited checking to improve congestion control") obsoleted in_flight parameter from tcp_is_cwnd_limited() and its callers. This patch does the removal as promised. Signed-off-by: NEric Dumazet <edumazet@google.com> Acked-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 03 5月, 2014 1 次提交
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由 Eric Dumazet 提交于
Yuchung discovered tcp_is_cwnd_limited() was returning false in slow start phase even if the application filled the socket write queue. All congestion modules take into account tcp_is_cwnd_limited() before increasing cwnd, so this behavior limits slow start from probing the bandwidth at full speed. The problem is that even if write queue is full (aka we are _not_ application limited), cwnd can be under utilized if TSO should auto defer or TCP Small queues decided to hold packets. So the in_flight can be kept to smaller value, and we can get to the point tcp_is_cwnd_limited() returns false. With TCP Small Queues and FQ/pacing, this issue is more visible. We fix this by having tcp_cwnd_validate(), which is supposed to track such things, take into account unsent_segs, the number of segs that we are not sending at the moment due to TSO or TSQ, but intend to send real soon. Then when we are cwnd-limited, remember this fact while we are processing the window of ACKs that comes back. For example, suppose we have a brand new connection with cwnd=10; we are in slow start, and we send a flight of 9 packets. By the time we have received ACKs for all 9 packets we want our cwnd to be 18. We implement this by setting tp->lsnd_pending to 9, and considering ourselves to be cwnd-limited while cwnd is less than twice tp->lsnd_pending (2*9 -> 18). This makes tcp_is_cwnd_limited() more understandable, by removing the GSO/TSO kludge, that tried to work around the issue. Note the in_flight parameter can be removed in a followup cleanup patch. Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NYuchung Cheng <ycheng@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 21 4月, 2014 1 次提交
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由 Weiping Pan 提交于
Make tcp_cwnd_application_limited() static and move it from tcp_input.c to tcp_output.c Signed-off-by: NWeiping Pan <wpan@redhat.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 21 3月, 2014 1 次提交
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由 Eric Dumazet 提交于
While it is true that getnstimeofday() uses about 40 cycles if TSC is available, it can use 1600 cycles if hpet is the clocksource. Switch to get_jiffies_64(), as this is more than enough, and go back to 60 seconds periods. Fixes: 8c27bd75 ("tcp: syncookies: reduce cookie lifetime to 128 seconds") Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Florian Westphal <fw@strlen.de> Acked-by: NFlorian Westphal <fw@strlen.de> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 27 2月, 2014 1 次提交
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由 Eric Dumazet 提交于
Upcoming congestion controls for TCP require usec resolution for RTT estimations. Millisecond resolution is simply not enough these days. FQ/pacing in DC environments also require this change for finer control and removal of bimodal behavior due to the current hack in tcp_update_pacing_rate() for 'small rtt' TCP_CONG_RTT_STAMP is no longer needed. As Julian Anastasov pointed out, we need to keep user compatibility : tcp_metrics used to export RTT and RTTVAR in msec resolution, so we added RTT_US and RTTVAR_US. An iproute2 patch is needed to use the new attributes if provided by the kernel. In this example ss command displays a srtt of 32 usecs (10Gbit link) lpk51:~# ./ss -i dst lpk52 Netid State Recv-Q Send-Q Local Address:Port Peer Address:Port tcp ESTAB 0 1 10.246.11.51:42959 10.246.11.52:64614 cubic wscale:6,6 rto:201 rtt:0.032/0.001 ato:40 mss:1448 cwnd:10 send 3620.0Mbps pacing_rate 7240.0Mbps unacked:1 rcv_rtt:993 rcv_space:29559 Updated iproute2 ip command displays : lpk51:~# ./ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 274us rttvar 213us source 10.246.11.51 Old binary displays : lpk51:~# ip tcp_metrics | grep 10.246.11.52 10.246.11.52 age 561.914sec cwnd 10 rtt 250us rttvar 125us source 10.246.11.51 With help from Julian Anastasov, Stephen Hemminger and Yuchung Cheng Signed-off-by: NEric Dumazet <edumazet@google.com> Acked-by: NNeal Cardwell <ncardwell@google.com> Cc: Stephen Hemminger <stephen@networkplumber.org> Cc: Yuchung Cheng <ycheng@google.com> Cc: Larry Brakmo <brakmo@google.com> Cc: Julian Anastasov <ja@ssi.bg> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 22 2月, 2014 1 次提交
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由 Eric Dumazet 提交于
This patch fixes two bugs in fastopen : 1) The tcp_sendmsg(..., @size) argument was ignored. Code was relying on user not fooling the kernel with iovec mismatches 2) When MTU is about 64KB, tcp_send_syn_data() attempts order-5 allocations, which are likely to fail when memory gets fragmented. Fixes: 783237e8 ("net-tcp: Fast Open client - sending SYN-data") Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: NYuchung Cheng <ycheng@google.com> Tested-by: NYuchung Cheng <ycheng@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 14 2月, 2014 1 次提交
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由 Stanislav Fomichev 提交于
Commit 684bad11 "tcp: use PRR to reduce cwin in CWR state" removed all calls to min_cwnd, so we can safely remove it. Also, remove tcp_reno_min_cwnd because it was only used for min_cwnd. Signed-off-by: NStanislav Fomichev <stfomichev@yandex-team.ru> Acked-by: NYuchung Cheng <ycheng@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 30 12月, 2013 1 次提交
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由 stephen hemminger 提交于
The following are only used in one file: tcp_connect_init tcp_set_rto Signed-off-by: NStephen Hemminger <stephen@networkplumber.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 18 12月, 2013 1 次提交
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由 Eric Dumazet 提交于
While investigating performance problems on small RPC workloads, I noticed linux TCP stack was always splitting the last TSO skb into two parts (skbs). One being a multiple of MSS, and a small one with the Push flag. This split is done even if TCP_NODELAY is set, or if no small packet is in flight. Example with request/response of 4K/4K IP A > B: . ack 68432 win 2783 <nop,nop,timestamp 6524593 6525001> IP A > B: . 65537:68433(2896) ack 69632 win 2783 <nop,nop,timestamp 6524593 6525001> IP A > B: P 68433:69633(1200) ack 69632 win 2783 <nop,nop,timestamp 6524593 6525001> IP B > A: . ack 68433 win 2768 <nop,nop,timestamp 6525001 6524593> IP B > A: . 69632:72528(2896) ack 69633 win 2768 <nop,nop,timestamp 6525001 6524593> IP B > A: P 72528:73728(1200) ack 69633 win 2768 <nop,nop,timestamp 6525001 6524593> IP A > B: . ack 72528 win 2783 <nop,nop,timestamp 6524593 6525001> IP A > B: . 69633:72529(2896) ack 73728 win 2783 <nop,nop,timestamp 6524593 6525001> IP A > B: P 72529:73729(1200) ack 73728 win 2783 <nop,nop,timestamp 6524593 6525001> We can avoid this split by including the Nagle tests at the right place. Note : If some NIC had trouble sending TSO packets with a partial last segment, we would have hit the problem in GRO/forwarding workload already. tcp_minshall_update() is moved to tcp_output.c and is updated as we might feed a TSO packet with a partial last segment. This patch tremendously improves performance, as the traffic now looks like : IP A > B: . ack 98304 win 2783 <nop,nop,timestamp 6834277 6834685> IP A > B: P 94209:98305(4096) ack 98304 win 2783 <nop,nop,timestamp 6834277 6834685> IP B > A: . ack 98305 win 2768 <nop,nop,timestamp 6834686 6834277> IP B > A: P 98304:102400(4096) ack 98305 win 2768 <nop,nop,timestamp 6834686 6834277> IP A > B: . ack 102400 win 2783 <nop,nop,timestamp 6834279 6834686> IP A > B: P 98305:102401(4096) ack 102400 win 2783 <nop,nop,timestamp 6834279 6834686> IP B > A: . ack 102401 win 2768 <nop,nop,timestamp 6834687 6834279> IP B > A: P 102400:106496(4096) ack 102401 win 2768 <nop,nop,timestamp 6834687 6834279> IP A > B: . ack 106496 win 2783 <nop,nop,timestamp 6834280 6834687> IP A > B: P 102401:106497(4096) ack 106496 win 2783 <nop,nop,timestamp 6834280 6834687> IP B > A: . ack 106497 win 2768 <nop,nop,timestamp 6834688 6834280> IP B > A: P 106496:110592(4096) ack 106497 win 2768 <nop,nop,timestamp 6834688 6834280> Before : lpq83:~# nstat >/dev/null;perf stat ./super_netperf 200 -t TCP_RR -H lpq84 -l 20 -- -r 4K,4K 280774 Performance counter stats for './super_netperf 200 -t TCP_RR -H lpq84 -l 20 -- -r 4K,4K': 205719.049006 task-clock # 9.278 CPUs utilized 8,449,968 context-switches # 0.041 M/sec 1,935,997 CPU-migrations # 0.009 M/sec 160,541 page-faults # 0.780 K/sec 548,478,722,290 cycles # 2.666 GHz [83.20%] 455,240,670,857 stalled-cycles-frontend # 83.00% frontend cycles idle [83.48%] 272,881,454,275 stalled-cycles-backend # 49.75% backend cycles idle [66.73%] 166,091,460,030 instructions # 0.30 insns per cycle # 2.74 stalled cycles per insn [83.39%] 29,150,229,399 branches # 141.699 M/sec [83.30%] 1,943,814,026 branch-misses # 6.67% of all branches [83.32%] 22.173517844 seconds time elapsed lpq83:~# nstat | egrep "IpOutRequests|IpExtOutOctets" IpOutRequests 16851063 0.0 IpExtOutOctets 23878580777 0.0 After patch : lpq83:~# nstat >/dev/null;perf stat ./super_netperf 200 -t TCP_RR -H lpq84 -l 20 -- -r 4K,4K 280877 Performance counter stats for './super_netperf 200 -t TCP_RR -H lpq84 -l 20 -- -r 4K,4K': 107496.071918 task-clock # 4.847 CPUs utilized 5,635,458 context-switches # 0.052 M/sec 1,374,707 CPU-migrations # 0.013 M/sec 160,920 page-faults # 0.001 M/sec 281,500,010,924 cycles # 2.619 GHz [83.28%] 228,865,069,307 stalled-cycles-frontend # 81.30% frontend cycles idle [83.38%] 142,462,742,658 stalled-cycles-backend # 50.61% backend cycles idle [66.81%] 95,227,712,566 instructions # 0.34 insns per cycle # 2.40 stalled cycles per insn [83.43%] 16,209,868,171 branches # 150.795 M/sec [83.20%] 874,252,952 branch-misses # 5.39% of all branches [83.37%] 22.175821286 seconds time elapsed lpq83:~# nstat | egrep "IpOutRequests|IpExtOutOctets" IpOutRequests 11239428 0.0 IpExtOutOctets 23595191035 0.0 Indeed, the occupancy of tx skbs (IpExtOutOctets/IpOutRequests) is higher : 2099 instead of 1417, thus helping GRO to be more efficient when using FQ packet scheduler. Many thanks to Neal for review and ideas. Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: Van Jacobson <vanj@google.com> Acked-by: NNeal Cardwell <ncardwell@google.com> Tested-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 07 12月, 2013 1 次提交
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由 Eric Dumazet 提交于
With the introduction of TCP Small Queues, TSO auto sizing, and TCP pacing, we can implement Automatic Corking in the kernel, to help applications doing small write()/sendmsg() to TCP sockets. Idea is to change tcp_push() to check if the current skb payload is under skb optimal size (a multiple of MSS bytes) If under 'size_goal', and at least one packet is still in Qdisc or NIC TX queues, set the TCP Small Queue Throttled bit, so that the push will be delayed up to TX completion time. This delay might allow the application to coalesce more bytes in the skb in following write()/sendmsg()/sendfile() system calls. The exact duration of the delay is depending on the dynamics of the system, and might be zero if no packet for this flow is actually held in Qdisc or NIC TX ring. Using FQ/pacing is a way to increase the probability of autocorking being triggered. Add a new sysctl (/proc/sys/net/ipv4/tcp_autocorking) to control this feature and default it to 1 (enabled) Add a new SNMP counter : nstat -a | grep TcpExtTCPAutoCorking This counter is incremented every time we detected skb was under used and its flush was deferred. Tested: Interesting effects when using line buffered commands under ssh. Excellent performance results in term of cpu usage and total throughput. lpq83:~# echo 1 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 9410.39 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 35209.439626 task-clock # 2.901 CPUs utilized 2,294 context-switches # 0.065 K/sec 101 CPU-migrations # 0.003 K/sec 4,079 page-faults # 0.116 K/sec 97,923,241,298 cycles # 2.781 GHz [83.31%] 51,832,908,236 stalled-cycles-frontend # 52.93% frontend cycles idle [83.30%] 25,697,986,603 stalled-cycles-backend # 26.24% backend cycles idle [66.70%] 102,225,978,536 instructions # 1.04 insns per cycle # 0.51 stalled cycles per insn [83.38%] 18,657,696,819 branches # 529.906 M/sec [83.29%] 91,679,646 branch-misses # 0.49% of all branches [83.40%] 12.136204899 seconds time elapsed lpq83:~# echo 0 >/proc/sys/net/ipv4/tcp_autocorking lpq83:~# perf stat ./super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128 6624.89 Performance counter stats for './super_netperf 4 -t TCP_STREAM -H lpq84 -- -m 128': 40045.864494 task-clock # 3.301 CPUs utilized 171 context-switches # 0.004 K/sec 53 CPU-migrations # 0.001 K/sec 4,080 page-faults # 0.102 K/sec 111,340,458,645 cycles # 2.780 GHz [83.34%] 61,778,039,277 stalled-cycles-frontend # 55.49% frontend cycles idle [83.31%] 29,295,522,759 stalled-cycles-backend # 26.31% backend cycles idle [66.67%] 108,654,349,355 instructions # 0.98 insns per cycle # 0.57 stalled cycles per insn [83.34%] 19,552,170,748 branches # 488.244 M/sec [83.34%] 157,875,417 branch-misses # 0.81% of all branches [83.34%] 12.130267788 seconds time elapsed Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 05 11月, 2013 1 次提交
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由 Yuchung Cheng 提交于
Slow start now increases cwnd by 1 if an ACK acknowledges some packets, regardless the number of packets. Consequently slow start performance is highly dependent on the degree of the stretch ACKs caused by receiver or network ACK compression mechanisms (e.g., delayed-ACK, GRO, etc). But slow start algorithm is to send twice the amount of packets of packets left so it should process a stretch ACK of degree N as if N ACKs of degree 1, then exits when cwnd exceeds ssthresh. A follow up patch will use the remainder of the N (if greater than 1) to adjust cwnd in the congestion avoidance phase. In addition this patch retires the experimental limited slow start (LSS) feature. LSS has multiple drawbacks but questionable benefit. The fractional cwnd increase in LSS requires a loop in slow start even though it's rarely used. Configuring such an increase step via a global sysctl on different BDPS seems hard. Finally and most importantly the slow start overshoot concern is now better covered by the Hybrid slow start (hystart) enabled by default. Signed-off-by: NYuchung Cheng <ycheng@google.com> Signed-off-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 22 10月, 2013 1 次提交
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由 Eric W. Biederman 提交于
The code that is implemented is per memory cgroup not per netns, and having per netns bits is just confusing. Remove the per netns bits to make it easier to see what is really going on. Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 20 10月, 2013 2 次提交
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由 Hannes Frederic Sowa 提交于
Changed key initialization of tcp_fastopen cookies to net_get_random_once. If the user sets a custom key net_get_random_once must be called at least once to ensure we don't overwrite the user provided key when the first cookie is generated later on. Cc: Yuchung Cheng <ycheng@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Hannes Frederic Sowa 提交于
This patch splits the secret key for syncookies for ipv4 and ipv6 and initializes them with net_get_random_once. This change was the reason I did this series. I think the initialization of the syncookie_secret is way to early. Cc: Florian Westphal <fw@strlen.de> Cc: Eric Dumazet <edumazet@google.com> Cc: "David S. Miller" <davem@davemloft.net> Signed-off-by: NHannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 19 10月, 2013 1 次提交
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由 Eric Dumazet 提交于
Rename tcp_tso_segment() to tcp_gso_segment(), to better reflect what is going on, and ease grep games. Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 11 10月, 2013 1 次提交
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由 Eric Dumazet 提交于
In commit 634fb979 ("inet: includes a sock_common in request_sock") I forgot that the two ports in sock_common do not have same byte order : skc_dport is __be16 (network order), but skc_num is __u16 (host order) So sparse complains because ir_loc_port (mapped into skc_num) is considered as __u16 while it should be __be16 Let rename ir_loc_port to ireq->ir_num (analogy with inet->inet_num), and perform appropriate htons/ntohs conversions. Signed-off-by: NEric Dumazet <edumazet@google.com> Reported-by: NWu Fengguang <fengguang.wu@intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 10 10月, 2013 1 次提交
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由 Eric Dumazet 提交于
TCP listener refactoring, part 5 : We want to be able to insert request sockets (SYN_RECV) into main ehash table instead of the per listener hash table to allow RCU lookups and remove listener lock contention. This patch includes the needed struct sock_common in front of struct request_sock This means there is no more inet6_request_sock IPv6 specific structure. Following inet_request_sock fields were renamed as they became macros to reference fields from struct sock_common. Prefix ir_ was chosen to avoid name collisions. loc_port -> ir_loc_port loc_addr -> ir_loc_addr rmt_addr -> ir_rmt_addr rmt_port -> ir_rmt_port iif -> ir_iif Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 09 10月, 2013 1 次提交
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由 Eric Dumazet 提交于
TCP listener refactoring, part 3 : Our goal is to hash SYN_RECV sockets into main ehash for fast lookup, and parallel SYN processing. Current inet_ehash_bucket contains two chains, one for ESTABLISH (and friend states) sockets, another for TIME_WAIT sockets only. As the hash table is sized to get at most one socket per bucket, it makes little sense to have separate twchain, as it makes the lookup slightly more complicated, and doubles hash table memory usage. If we make sure all socket types have the lookup keys at the same offsets, we can use a generic and faster lookup. It turns out TIME_WAIT and ESTABLISHED sockets already have common lookup fields for IPv4. [ INET_TW_MATCH() is no longer needed ] I'll provide a follow-up to factorize IPv6 lookup as well, to remove INET6_TW_MATCH() This way, SYN_RECV pseudo sockets will be supported the same. A new sock_gen_put() helper is added, doing either a sock_put() or inet_twsk_put() [ and will support SYN_RECV later ]. Note this helper should only be called in real slow path, when rcu lookup found a socket that was moved to another identity (freed/reused immediately), but could eventually be used in other contexts, like sock_edemux() Before patch : dmesg | grep "TCP established" TCP established hash table entries: 524288 (order: 11, 8388608 bytes) After patch : TCP established hash table entries: 524288 (order: 10, 4194304 bytes) Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 24 9月, 2013 2 次提交
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由 Florian Westphal 提交于
We currently accept cookies that were created less than 4 minutes ago (ie, cookies with counter delta 0-3). Combined with the 8 mss table values, this yields 32 possible values (out of 2**32) that will be valid. Reducing the lifetime to < 2 minutes halves the guessing chance while still providing a large enough period. While at it, get rid of jiffies value -- they overflow too quickly on 32 bit platforms. getnstimeofday is used to create a counter that increments every 64s. perf shows getnstimeofday cost is negible compared to sha_transform; normal tcp initial sequence number generation uses getnstimeofday, too. Reported-by: NJakob Lell <jakob@jakoblell.com> Signed-off-by: NFlorian Westphal <fw@strlen.de> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Joe Perches 提交于
There are a mix of function prototypes with and without extern in the kernel sources. Standardize on not using extern for function prototypes. Function prototypes don't need to be written with extern. extern is assumed by the compiler. Its use is as unnecessary as using auto to declare automatic/local variables in a block. Signed-off-by: NJoe Perches <joe@perches.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 04 9月, 2013 1 次提交
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由 Vijay Subramanian 提交于
tcp_rcv_established() returns only one value namely 0. We change the return value to void (as suggested by David Miller). After commit 0c24604b (tcp: implement RFC 5961 4.2), we no longer send RSTs in response to SYNs. We can remove the check and processing on the return value of tcp_rcv_established(). We also fix jtcp_rcv_established() in tcp_probe.c to match that of tcp_rcv_established(). Signed-off-by: NVijay Subramanian <subramanian.vijay@gmail.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 30 8月, 2013 1 次提交
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由 Eric Dumazet 提交于
After hearing many people over past years complaining against TSO being bursty or even buggy, we are proud to present automatic sizing of TSO packets. One part of the problem is that tcp_tso_should_defer() uses an heuristic relying on upcoming ACKS instead of a timer, but more generally, having big TSO packets makes little sense for low rates, as it tends to create micro bursts on the network, and general consensus is to reduce the buffering amount. This patch introduces a per socket sk_pacing_rate, that approximates the current sending rate, and allows us to size the TSO packets so that we try to send one packet every ms. This field could be set by other transports. Patch has no impact for high speed flows, where having large TSO packets makes sense to reach line rate. For other flows, this helps better packet scheduling and ACK clocking. This patch increases performance of TCP flows in lossy environments. A new sysctl (tcp_min_tso_segs) is added, to specify the minimal size of a TSO packet (default being 2). A follow-up patch will provide a new packet scheduler (FQ), using sk_pacing_rate as an input to perform optional per flow pacing. This explains why we chose to set sk_pacing_rate to twice the current rate, allowing 'slow start' ramp up. sk_pacing_rate = 2 * cwnd * mss / srtt v2: Neal Cardwell reported a suspect deferring of last two segments on initial write of 10 MSS, I had to change tcp_tso_should_defer() to take into account tp->xmit_size_goal_segs Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Van Jacobson <vanj@google.com> Cc: Tom Herbert <therbert@google.com> Acked-by: NYuchung Cheng <ycheng@google.com> Acked-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 28 8月, 2013 1 次提交
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由 Patrick McHardy 提交于
Extract the local TCP stack independant parts of tcp_v6_init_sequence() and cookie_v6_check() and export them for use by the upcoming IPv6 SYNPROXY target. Signed-off-by: NPatrick McHardy <kaber@trash.net> Acked-by: NDavid S. Miller <davem@davemloft.net> Tested-by: NMartin Topholm <mph@one.com> Signed-off-by: NJesper Dangaard Brouer <brouer@redhat.com> Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>
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