- 21 12月, 2013 1 次提交
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由 Eric Dumazet 提交于
Willem noticed a TCP_RR regression caused by TCP autocorking on a Mellanox test bed. MLX4_EN_TX_COAL_TIME is 16 us, which can be right above RTT between hosts. We can receive a ACK for a packet still in NIC TX ring buffer or in a softnet completion queue. Fix this by always pushing the skb if it is at the head of write queue. Also, as TX completion is lockless, it's safer to perform sk_wmem_alloc test after setting TSQ_THROTTLED. erd:~# MIB="MIN_LATENCY,MEAN_LATENCY,MAX_LATENCY,P99_LATENCY,STDDEV_LATENCY" erd:~# ./netperf -H remote -t TCP_RR -- -o $MIB | tail -n 1 (repeat 3 times) Before patch : 18,1049.87,41004,39631,6295.47 17,239.52,40804,48,2912.79 18,348.40,40877,54,3573.39 After patch : 18,22.84,4606,38,16.39 17,21.56,2871,36,13.51 17,22.46,2705,37,11.83 Reported-by: NWillem de Bruijn <willemb@google.com> Signed-off-by: NEric Dumazet <edumazet@google.com> Fixes: f54b3111 ("tcp: auto corking") 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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- 15 11月, 2013 1 次提交
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由 Eric Dumazet 提交于
After commit c9eeec26 ("tcp: TSQ can use a dynamic limit"), several users reported throughput regressions, notably on mvneta and wifi adapters. 802.11 AMPDU requires a fair amount of queueing to be effective. This patch partially reverts the change done in tcp_write_xmit() so that the minimal amount is sysctl_tcp_limit_output_bytes. It also remove the use of this sysctl while building skb stored in write queue, as TSO autosizing does the right thing anyway. Users with well behaving NICS and correct qdisc (like sch_fq), can then lower the default sysctl_tcp_limit_output_bytes value from 128KB to 8KB. This new usage of sysctl_tcp_limit_output_bytes permits each driver authors to check how their driver performs when/if the value is set to a minimum of 4KB. Normally, line rate for a single TCP flow should be possible, but some drivers rely on timers to perform TX completion and too long TX completion delays prevent reaching full throughput. Fixes: c9eeec26 ("tcp: TSQ can use a dynamic limit") Signed-off-by: NEric Dumazet <edumazet@google.com> Reported-by: NSujith Manoharan <sujith@msujith.org> Reported-by: NArnaud Ebalard <arno@natisbad.org> Tested-by: NSujith Manoharan <sujith@msujith.org> Cc: Felix Fietkau <nbd@openwrt.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 25 10月, 2013 1 次提交
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由 Vinod Koul 提交于
Acked-by: NDavid S. Miller <davem@davemloft.net> Acked-by: NDan Williams <dan.j.williams@intel.com> Acked-by: NLinus Walleij <linus.walleij@linaro.org> Signed-off-by: NVinod Koul <vinod.koul@intel.com>
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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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- 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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- 06 9月, 2013 1 次提交
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由 Dave Jones 提交于
Signed-off-by: NDave Jones <davej@fedoraproject.org> Acked-by: NNeal Cardwell <ncardwell@google.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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- 21 8月, 2013 1 次提交
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由 Andrey Vagin 提交于
When the repair mode is turned off, the write queue seqs are updated so that the whole queue is considered to be 'already sent. The "when" field must be set for such skb. It's used in tcp_rearm_rto for example. If the "when" field isn't set, the retransmit timeout can be calculated incorrectly and a tcp connected can stop for two minutes (TCP_RTO_MAX). Acked-by: NPavel Emelyanov <xemul@parallels.com> Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: James Morris <jmorris@namei.org> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: Patrick McHardy <kaber@trash.net> Signed-off-by: NAndrey Vagin <avagin@openvz.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 01 8月, 2013 1 次提交
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由 Dmitry Popov 提交于
Remove declaration, 4 defines and confusing comment that are no longer used since 1a2c6181 ("tcp: Remove TCPCT"). Signed-off-by: NDmitry Popov <dp@highloadlab.com> Acked-by: NChristoph Paasch <christoph.paasch@uclouvain.be> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 25 7月, 2013 2 次提交
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由 Eric Dumazet 提交于
Idea of this patch is to add optional limitation of number of unsent bytes in TCP sockets, to reduce usage of kernel memory. TCP receiver might announce a big window, and TCP sender autotuning might allow a large amount of bytes in write queue, but this has little performance impact if a large part of this buffering is wasted : Write queue needs to be large only to deal with large BDP, not necessarily to cope with scheduling delays (incoming ACKS make room for the application to queue more bytes) For most workloads, using a value of 128 KB or less is OK to give applications enough time to react to POLLOUT events in time (or being awaken in a blocking sendmsg()) This patch adds two ways to set the limit : 1) Per socket option TCP_NOTSENT_LOWAT 2) A sysctl (/proc/sys/net/ipv4/tcp_notsent_lowat) for sockets not using TCP_NOTSENT_LOWAT socket option (or setting a zero value) Default value being UINT_MAX (0xFFFFFFFF), meaning this has no effect. This changes poll()/select()/epoll() to report POLLOUT only if number of unsent bytes is below tp->nosent_lowat Note this might increase number of sendmsg()/sendfile() calls when using non blocking sockets, and increase number of context switches for blocking sockets. Note this is not related to SO_SNDLOWAT (as SO_SNDLOWAT is defined as : Specify the minimum number of bytes in the buffer until the socket layer will pass the data to the protocol) Tested: netperf sessions, and watching /proc/net/protocols "memory" column for TCP With 200 concurrent netperf -t TCP_STREAM sessions, amount of kernel memory used by TCP buffers shrinks by ~55 % (20567 pages instead of 45458) lpq83:~# echo -1 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# (super_netperf 200 -t TCP_STREAM -H remote -l 90 &); sleep 60 ; grep TCP /proc/net/protocols TCPv6 1880 2 45458 no 208 yes ipv6 y y y y y y y y y y y y y n y y y y y TCP 1696 508 45458 no 208 yes kernel y y y y y y y y y y y y y n y y y y y lpq83:~# echo 131072 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# (super_netperf 200 -t TCP_STREAM -H remote -l 90 &); sleep 60 ; grep TCP /proc/net/protocols TCPv6 1880 2 20567 no 208 yes ipv6 y y y y y y y y y y y y y n y y y y y TCP 1696 508 20567 no 208 yes kernel y y y y y y y y y y y y y n y y y y y Using 128KB has no bad effect on the throughput or cpu usage of a single flow, although there is an increase of context switches. A bonus is that we hold socket lock for a shorter amount of time and should improve latencies of ACK processing. lpq83:~# echo -1 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# perf stat -e context-switches ./netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3 OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : +/-2.500% @ 99% conf. Local Remote Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service Send Socket Recv Socket Send Time Units CPU CPU CPU CPU Service Service Demand Size Size Size (sec) Util Util Util Util Demand Demand Units Final Final % Method % Method 1651584 6291456 16384 20.00 17447.90 10^6bits/s 3.13 S -1.00 U 0.353 -1.000 usec/KB Performance counter stats for './netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3': 412,514 context-switches 200.034645535 seconds time elapsed lpq83:~# echo 131072 >/proc/sys/net/ipv4/tcp_notsent_lowat lpq83:~# perf stat -e context-switches ./netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3 OMNI Send TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.7.84 () port 0 AF_INET : +/-2.500% @ 99% conf. Local Remote Local Elapsed Throughput Throughput Local Local Remote Remote Local Remote Service Send Socket Recv Socket Send Time Units CPU CPU CPU CPU Service Service Demand Size Size Size (sec) Util Util Util Util Demand Demand Units Final Final % Method % Method 1593240 6291456 16384 20.00 17321.16 10^6bits/s 3.35 S -1.00 U 0.381 -1.000 usec/KB Performance counter stats for './netperf -H 7.7.7.84 -t omni -l 20 -c -i10,3': 2,675,818 context-switches 200.029651391 seconds time elapsed Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-By: NYuchung Cheng <ycheng@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Eric Dumazet 提交于
Several call sites use the hardcoded following condition : sk_stream_wspace(sk) >= sk_stream_min_wspace(sk) Lets use a helper because TCP_NOTSENT_LOWAT support will change this condition for TCP sockets. Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Acked-by: NNeal Cardwell <ncardwell@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 11 7月, 2013 1 次提交
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由 Eliezer Tamir 提交于
Rename the file and correct all the places where it is included. Signed-off-by: NEliezer Tamir <eliezer.tamir@linux.intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 09 7月, 2013 1 次提交
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由 Eliezer Tamir 提交于
Rename functions in include/net/ll_poll.h to busy wait. Clarify documentation about expected power use increase. Rename POLL_LL to POLL_BUSY_LOOP. Add need_resched() testing to poll/select busy loops. Note, that in select and poll can_busy_poll is dynamic and is updated continuously to reflect the existence of supported sockets with valid queue information. Signed-off-by: NEliezer Tamir <eliezer.tamir@linux.intel.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 11 6月, 2013 1 次提交
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由 Eliezer Tamir 提交于
Adds low latency socket poll support for TCP. In tcp_v[46]_rcv() add a call to sk_mark_ll() to copy the napi_id from the skb to the sk. In tcp_recvmsg(), when there is no data in the socket we busy-poll. This is a good example of how to add busy-poll support to more protocols. Signed-off-by: NAlexander Duyck <alexander.h.duyck@intel.com> Signed-off-by: NJesse Brandeburg <jesse.brandeburg@intel.com> Signed-off-by: NEliezer Tamir <eliezer.tamir@linux.intel.com> Acked-by: NEric Dumazet <edumazet@google.com> Tested-by: NWillem de Bruijn <willemb@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 08 6月, 2013 2 次提交
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由 Daniel Borkmann 提交于
Would be good to make things explicit and move those functions to a new file called tcp_offload.c, thus make this similar to tcpv6_offload.c. While moving all related functions into tcp_offload.c, we can also make some of them static, since they are only used there. Also, add an explicit registration function. Suggested-by: NEric Dumazet <eric.dumazet@gmail.com> Signed-off-by: NDaniel Borkmann <dborkman@redhat.com> Acked-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Daniel Borkmann 提交于
We have the minimal inline helper tcp_skb_mss to access skb_shinfo(skb)->gso_size, so also use it here to get mss. Signed-off-by: NDaniel Borkmann <dborkman@redhat.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 01 6月, 2013 1 次提交
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由 David Majnemer 提交于
The current state of affairs is that read()/write() will setup RFS (Receive Flow Steering) for internet protocol sockets while poll()/epoll() does not. When poll() gets called with a TCP or UDP socket, we should update the flow target. This permits to RFS (if enabled) to select the appropriate CPU for following incoming packets. Note: Only connected UDP sockets can benefit from RFS. Signed-off-by: NDavid Majnemer <majnemer@google.com> Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Paul Turner <pjt@google.com> Cc: Tom Herbert <therbert@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 29 5月, 2013 1 次提交
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由 Simon Horman 提交于
This corrects an regression introduced by "net: Use 16bits for *_headers fields of struct skbuff" when NET_SKBUFF_DATA_USES_OFFSET is not set. In that case skb->tail will be a pointer whereas skb->transport_header will be an offset from head. This is corrected by using wrappers that ensure that comparisons and calculations are always made using pointers. Signed-off-by: NSimon Horman <horms@verge.net.au> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 28 5月, 2013 1 次提交
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由 Simon Horman 提交于
In the case where a non-MPLS packet is received and an MPLS stack is added it may well be the case that the original skb is GSO but the NIC used for transmit does not support GSO of MPLS packets. The aim of this code is to provide GSO in software for MPLS packets whose skbs are GSO. SKB Usage: When an implementation adds an MPLS stack to a non-MPLS packet it should do the following to skb metadata: * Set skb->inner_protocol to the old non-MPLS ethertype of the packet. skb->inner_protocol is added by this patch. * Set skb->protocol to the new MPLS ethertype of the packet. * Set skb->network_header to correspond to the end of the L3 header, including the MPLS label stack. I have posted a patch, "[PATCH v3.29] datapath: Add basic MPLS support to kernel" which adds MPLS support to the kernel datapath of Open vSwtich. That patch sets the above requirements in datapath/actions.c:push_mpls() and was used to exercise this code. The datapath patch is against the Open vSwtich tree but it is intended that it be added to the Open vSwtich code present in the mainline Linux kernel at some point. Features: I believe that the approach that I have taken is at least partially consistent with the handling of other protocols. Jesse, I understand that you have some ideas here. I am more than happy to change my implementation. This patch adds dev->mpls_features which may be used by devices to advertise features supported for MPLS packets. A new NETIF_F_MPLS_GSO feature is added for devices which support hardware MPLS GSO offload. Currently no devices support this and MPLS GSO always falls back to software. Alternate Implementation: One possible alternate implementation is to teach netif_skb_features() and skb_network_protocol() about MPLS, in a similar way to their understanding of VLANs. I believe this would avoid the need for net/mpls/mpls_gso.c and in particular the calls to __skb_push() and __skb_push() in mpls_gso_segment(). I have decided on the implementation in this patch as it should not introduce any overhead in the case where mpls_gso is not compiled into the kernel or inserted as a module. MPLS GSO suggested by Jesse Gross. Based in part on "v4 GRE: Add TCP segmentation offload for GRE" by Pravin B Shelar. Cc: Jesse Gross <jesse@nicira.com> Cc: Pravin B Shelar <pshelar@nicira.com> Signed-off-by: NSimon Horman <horms@verge.net.au> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 21 5月, 2013 1 次提交
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由 Eric Dumazet 提交于
TCP md5 code uses per cpu variables but protects access to them with a shared spinlock, which is a contention point. [ tcp_md5sig_pool_lock is locked twice per incoming packet ] Makes things much simpler, by allocating crypto structures once, first time a socket needs md5 keys, and not deallocating them as they are really small. Next step would be to allow crypto allocations being done in a NUMA aware way. Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 17 5月, 2013 1 次提交
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由 Eric Dumazet 提交于
GSO TCP handler has following issues : 1) ooo_okay from original GSO packet is duplicated to all segments 2) segments (but the last one) are orphaned, so transmit path can not get transmit queue number from the socket. This happens if GSO segmentation is done before stacked device for example. Result is we can send packets from a given TCP flow to different TX queues (if using multiqueue NICS). This generates OOO problems and spurious SACK & retransmits. Fix this by keeping socket pointer set for all segments. This means that every segment must also have a destructor, and the original gso skb truesize must be split on all segments, to keep precise sk->sk_wmem_alloc accounting. Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Maciej Żenczykowski <maze@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Neal Cardwell <ncardwell@google.com> Cc: Yuchung Cheng <ycheng@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 15 5月, 2013 1 次提交
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由 Eric Dumazet 提交于
TCP md5 communications fail [1] for some devices, because sg/crypto code assume page offsets are below PAGE_SIZE. This was discovered using mlx4 driver [2], but I suspect loopback might trigger the same bug now we use order-3 pages in tcp_sendmsg() [1] Failure is giving following messages. huh, entered softirq 3 NET_RX ffffffff806ad230 preempt_count 00000100, exited with 00000101? [2] mlx4 driver uses order-2 pages to allocate RX frags Reported-by: NMatt Schnall <mischnal@google.com> Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Bernhard Beck <bbeck@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 14 4月, 2013 1 次提交
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由 Eric Dumazet 提交于
We can move th->check computation out of the loop, as compiler doesn't know each skb initially share same tcp headers after skb_segment() Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 13 4月, 2013 1 次提交
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由 Eric Dumazet 提交于
I noticed that TSQ (TCP Small queues) was less effective when TSO is turned off, and GSO is on. If BQL is not enabled, TSQ has then no effect. It turns out the GSO engine frees the original gso_skb at the time the fragments are generated and queued to the NIC. We should instead call the tcp_wfree() destructor for the last fragment, to keep the flow control as intended in TSQ. This effectively limits the number of queued packets on qdisc + NIC layers. Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Tom Herbert <therbert@google.com> Cc: Yuchung Cheng <ycheng@google.com> Cc: Nandita Dukkipati <nanditad@google.com> Cc: Neal Cardwell <ncardwell@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 18 3月, 2013 1 次提交
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由 Christoph Paasch 提交于
TCPCT uses option-number 253, reserved for experimental use and should not be used in production environments. Further, TCPCT does not fully implement RFC 6013. As a nice side-effect, removing TCPCT increases TCP's performance for very short flows: Doing an apache-benchmark with -c 100 -n 100000, sending HTTP-requests for files of 1KB size. before this patch: average (among 7 runs) of 20845.5 Requests/Second after: average (among 7 runs) of 21403.6 Requests/Second Signed-off-by: NChristoph Paasch <christoph.paasch@uclouvain.be> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 14 3月, 2013 1 次提交
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由 Eric Dumazet 提交于
Chrome OS team reported a crash on a Pixel ChromeBook in TCP stack : https://code.google.com/p/chromium/issues/detail?id=182056 commit a21d4572 (tcp: avoid order-1 allocations on wifi and tx path) did a poor choice adding an 'avail_size' field to skb, while what we really needed was a 'reserved_tailroom' one. It would have avoided commit 22b4a4f2 (tcp: fix retransmit of partially acked frames) and this commit. Crash occurs because skb_split() is not aware of the 'avail_size' management (and should not be aware) Signed-off-by: NEric Dumazet <edumazet@google.com> Reported-by: NMukesh Agrawal <quiche@chromium.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 10 3月, 2013 1 次提交
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由 Pravin B Shelar 提交于
Adds generic tunneling offloading support for IPv4-UDP based tunnels. GSO type is added to request this offload for a skb. netdev feature NETIF_F_UDP_TUNNEL is added for hardware offloaded udp-tunnel support. Currently no device supports this feature, software offload is used. This can be used by tunneling protocols like VXLAN. CC: Jesse Gross <jesse@nicira.com> Signed-off-by: NPravin B Shelar <pshelar@nicira.com> Acked-by: NStephen Hemminger <stephen@networkplumber.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 16 2月, 2013 1 次提交
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由 Pravin B Shelar 提交于
Following patch adds GRE protocol offload handler so that skb_gso_segment() can segment GRE packets. SKB GSO CB is added to keep track of total header length so that skb_segment can push entire header. e.g. in case of GRE, skb_segment need to push inner and outer headers to every segment. New NETIF_F_GRE_GSO feature is added for devices which support HW GRE TSO offload. Currently none of devices support it therefore GRE GSO always fall backs to software GSO. [ Compute pkt_len before ip_local_out() invocation. -DaveM ] Signed-off-by: NPravin B Shelar <pshelar@nicira.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 14 2月, 2013 3 次提交
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由 Pravin B Shelar 提交于
Patch cef401de (net: fix possible wrong checksum generation) fixed wrong checksum calculation but it broke TSO by defining new GSO type but not a netdev feature for that type. net_gso_ok() would not allow hardware checksum/segmentation offload of such packets without the feature. Following patch fixes TSO and wrong checksum. This patch uses same logic that Eric Dumazet used. Patch introduces new flag SKBTX_SHARED_FRAG if at least one frag can be modified by the user. but SKBTX_SHARED_FRAG flag is kept in skb shared info tx_flags rather than gso_type. tx_flags is better compared to gso_type since we can have skb with shared frag without gso packet. It does not link SHARED_FRAG to GSO, So there is no need to define netdev feature for this. Signed-off-by: NPravin B Shelar <pshelar@nicira.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Andrey Vagin 提交于
A timestamp can be set, only if a socket is in the repair mode. This patch adds a new socket option TCP_TIMESTAMP, which allows to get and set current tcp times stamp. Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: James Morris <jmorris@namei.org> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: NAndrey Vagin <avagin@openvz.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Andrey Vagin 提交于
This functionality is used for restoring tcp sockets. A tcp timestamp depends on how long a system has been running, so it's differ for each host. The solution is to set a per-socket offset. A per-socket offset for a TIME_WAIT socket is inherited from a proper tcp socket. tcp_request_sock doesn't have a timestamp offset, because the repair mode for them are not implemented. Cc: "David S. Miller" <davem@davemloft.net> Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: James Morris <jmorris@namei.org> Cc: Hideaki YOSHIFUJI <yoshfuji@linux-ipv6.org> Cc: Patrick McHardy <kaber@trash.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Pavel Emelyanov <xemul@parallels.com> Signed-off-by: NAndrey Vagin <avagin@openvz.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 06 2月, 2013 1 次提交
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由 Stephen Hemminger 提交于
TCP Appropriate Byte Count was added by me, but later disabled. There is no point in maintaining it since it is a potential source of bugs and Linux already implements other better window protection heuristics. Signed-off-by: NStephen Hemminger <stephen@networkplumber.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 28 1月, 2013 1 次提交
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由 Eric Dumazet 提交于
Pravin Shelar mentioned that GSO could potentially generate wrong TX checksum if skb has fragments that are overwritten by the user between the checksum computation and transmit. He suggested to linearize skbs but this extra copy can be avoided for normal tcp skbs cooked by tcp_sendmsg(). This patch introduces a new SKB_GSO_SHARED_FRAG flag, set in skb_shinfo(skb)->gso_type if at least one frag can be modified by the user. Typical sources of such possible overwrites are {vm}splice(), sendfile(), and macvtap/tun/virtio_net drivers. Tested: $ netperf -H 7.7.8.84 MIGRATED TCP STREAM TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.8.84 () port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 3959.52 $ netperf -H 7.7.8.84 -t TCP_SENDFILE TCP SENDFILE TEST from 0.0.0.0 (0.0.0.0) port 0 AF_INET to 7.7.8.84 () port 0 AF_INET Recv Send Send Socket Socket Message Elapsed Size Size Size Time Throughput bytes bytes bytes secs. 10^6bits/sec 87380 16384 16384 10.00 3216.80 Performance of the SENDFILE is impacted by the extra allocation and copy, and because we use order-0 pages, while the TCP_STREAM uses bigger pages. Reported-by: NPravin Shelar <pshelar@nicira.com> Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 23 1月, 2013 1 次提交
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由 YOSHIFUJI Hideaki / 吉藤英明 提交于
Signed-off-by: NYOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 11 1月, 2013 2 次提交
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由 Eric Dumazet 提交于
Under unusual circumstances, TCP collapse can split a big GRO TCP packet while its being used in a splice(socket->pipe) operation. skb_splice_bits() releases the socket lock before calling splice_to_pipe(). [ 1081.353685] WARNING: at net/ipv4/tcp.c:1330 tcp_cleanup_rbuf+0x4d/0xfc() [ 1081.371956] Hardware name: System x3690 X5 -[7148Z68]- [ 1081.391820] cleanup rbuf bug: copied AD3BCF1 seq AD370AF rcvnxt AD3CF13 To fix this problem, we must eat skbs in tcp_recv_skb(). Remove the inline keyword from tcp_recv_skb() definition since it has three call sites. Reported-by: NChristian Becker <c.becker@traviangames.com> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: NEric Dumazet <edumazet@google.com> Tested-by: NWilly Tarreau <w@1wt.eu> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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由 Eric Dumazet 提交于
commit 02275a2e (tcp: don't abort splice() after small transfers) added a regression. [ 83.843570] INFO: rcu_sched self-detected stall on CPU [ 83.844575] INFO: rcu_sched detected stalls on CPUs/tasks: { 6} (detected by 0, t=21002 jiffies, g=4457, c=4456, q=13132) [ 83.844582] Task dump for CPU 6: [ 83.844584] netperf R running task 0 8966 8952 0x0000000c [ 83.844587] 0000000000000000 0000000000000006 0000000000006c6c 0000000000000000 [ 83.844589] 000000000000006c 0000000000000096 ffffffff819ce2bc ffffffffffffff10 [ 83.844592] ffffffff81088679 0000000000000010 0000000000000246 ffff880c4b9ddcd8 [ 83.844594] Call Trace: [ 83.844596] [<ffffffff81088679>] ? vprintk_emit+0x1c9/0x4c0 [ 83.844601] [<ffffffff815ad449>] ? schedule+0x29/0x70 [ 83.844606] [<ffffffff81537bd2>] ? tcp_splice_data_recv+0x42/0x50 [ 83.844610] [<ffffffff8153beaa>] ? tcp_read_sock+0xda/0x260 [ 83.844613] [<ffffffff81537b90>] ? tcp_prequeue_process+0xb0/0xb0 [ 83.844615] [<ffffffff8153c0f0>] ? tcp_splice_read+0xc0/0x250 [ 83.844618] [<ffffffff814dc0c2>] ? sock_splice_read+0x22/0x30 [ 83.844622] [<ffffffff811b820b>] ? do_splice_to+0x7b/0xa0 [ 83.844627] [<ffffffff811ba4bc>] ? sys_splice+0x59c/0x5d0 [ 83.844630] [<ffffffff8119745b>] ? putname+0x2b/0x40 [ 83.844633] [<ffffffff8118bcb4>] ? do_sys_open+0x174/0x1e0 [ 83.844636] [<ffffffff815b6202>] ? system_call_fastpath+0x16/0x1b if recv_actor() returns 0, we should stop immediately, because looping wont give a chance to drain the pipe. Signed-off-by: NEric Dumazet <edumazet@google.com> Cc: Willy Tarreau <w@1wt.eu> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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- 08 1月, 2013 2 次提交
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Just use dma_async_is_tx_complete() directly. Cc: Vinod Koul <vinod.koul@intel.com> Cc: Tomasz Figa <t.figa@samsung.com> Signed-off-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com> Signed-off-by: NDan Williams <djbw@fb.com>
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Just use dma_async_issue_pending() directly. Cc: Vinod Koul <vinod.koul@intel.com> Cc: Tomasz Figa <t.figa@samsung.com> Signed-off-by: NBartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Signed-off-by: NKyungmin Park <kyungmin.park@samsung.com> Signed-off-by: NDan Williams <djbw@fb.com>
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- 03 12月, 2012 1 次提交
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由 Willy Tarreau 提交于
TCP coalescing added a regression in splice(socket->pipe) performance, for some workloads because of the way tcp_read_sock() is implemented. The reason for this is the break when (offset + 1 != skb->len). As we released the socket lock, this condition is possible if TCP stack added a fragment to the skb, which can happen with TCP coalescing. So let's go back to the beginning of the loop when this happens, to give a chance to splice more frags per system call. Doing so fixes the issue and makes GRO 10% faster than LRO on CPU-bound splice() workloads instead of the opposite. Signed-off-by: NWilly Tarreau <w@1wt.eu> Signed-off-by: NEric Dumazet <edumazet@google.com> Signed-off-by: NDavid S. Miller <davem@davemloft.net>
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