kernel/include/trace/events/tcp.h, branch linux-6.18.y

trace: tcp: add three metrics to trace_tcp_rcvbuf_grow()

2025-10-30T00:30:18Z

While chasing yet another receive autotuning bug, I found useful to add rcv_ssthresh, window_clamp and rcv_wnd. tcp_stream 40597 [068] 2172.978198: tcp:tcp_rcvbuf_grow: time=50307 rtt_us=50179 copied=77824 inq=0 space=40960 ooo=0 scaling_ratio=219 rcvbuf=131072 rcv_ssthresh=107474 window_clamp=112128 rcv_wnd=110592 tcp_stream 40597 [068] 2173.028528: tcp:tcp_rcvbuf_grow: time=50336 rtt_us=50206 copied=110592 inq=0 space=77824 ooo=0 scaling_ratio=219 rcvbuf=509444 rcv_ssthresh=328658 window_clamp=435813 rcv_wnd=331776 tcp_stream 40597 [068] 2173.078830: tcp:tcp_rcvbuf_grow: time=50305 rtt_us=50070 copied=270336 inq=0 space=110592 ooo=0 scaling_ratio=219 rcvbuf=509444 rcv_ssthresh=431159 window_clamp=435813 rcv_wnd=434176 tcp_stream 40597 [068] 2173.129137: tcp:tcp_rcvbuf_grow: time=50313 rtt_us=50118 copied=434176 inq=0 space=270336 ooo=0 scaling_ratio=219 rcvbuf=2457847 rcv_ssthresh=1299511 window_clamp=2102611 rcv_wnd=1302528 tcp_stream 40597 [068] 2173.179451: tcp:tcp_rcvbuf_grow: time=50318 rtt_us=50041 copied=1019904 inq=0 space=434176 ooo=0 scaling_ratio=219 rcvbuf=2457847 rcv_ssthresh=2087445 window_clamp=2102611 rcv_wnd=2088960 Signed-off-by: Eric Dumazet Signed-off-by: Matthieu Baerts (NGI0) Reviewed-by: Neal Cardwell Link: https://patch.msgid.link/20251028-net-tcp-recv-autotune-v3-2-74b43ba4c84c@kernel.org Signed-off-by: Jakub Kicinski

tcp: trace retransmit failures in tcp_retransmit_skb

2025-07-23T01:19:11Z

Background ========== When TCP retransmits a packet due to missing ACKs, the retransmission may fail for various reasons (e.g., packets stuck in driver queues, receiver zero windows, or routing issues). The original tcp_retransmit_skb tracepoint: 'commit e086101b150a ("tcp: add a tracepoint for tcp retransmission")' lacks visibility into these failure causes, making production diagnostics difficult. Solution ======== Adds the retval("err") to the tcp_retransmit_skb tracepoint. Enables users to know why some tcp retransmission failed and users can filter retransmission failures by retval. Compatibility description ========================= This patch extends the tcp_retransmit_skb tracepoint by adding a new "err" field at the end of its existing structure (within TP_STRUCT__entry). The compatibility implications are detailed as follows: 1) Structural compatibility for legacy user-space tools Legacy tools/BPF programs accessing existing fields (by offset or name) can still work without modification or recompilation.The new field is appended to the end, preserving original memory layout. 2) Note: semantic changes The original tracepoint primarily only focused on successfully retransmitted packets. With this patch, the tracepoint now can figure out packets that may terminate early due to specific reasons. For accurate statistics, users should filter using "err" to distinguish outcomes. Before patched: field:const void * skbaddr; offset:8; size:8; signed:0; field:const void * skaddr; offset:16; size:8; signed:0; field:int state; offset:24; size:4; signed:1; field:__u16 sport; offset:28; size:2; signed:0; field:__u16 dport; offset:30; size:2; signed:0; field:__u16 family; offset:32; size:2; signed:0; field:__u8 saddr[4]; offset:34; size:4; signed:0; field:__u8 daddr[4]; offset:38; size:4; signed:0; field:__u8 saddr_v6[16]; offset:42; size:16; signed:0; field:__u8 daddr_v6[16]; offset:58; size:16; signed:0; print fmt: "skbaddr=%p skaddr=%p family=%s sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c state=%s" After patched: field:const void * skbaddr; offset:8; size:8; signed:0; field:const void * skaddr; offset:16; size:8; signed:0; field:int state; offset:24; size:4; signed:1; field:__u16 sport; offset:28; size:2; signed:0; field:__u16 dport; offset:30; size:2; signed:0; field:__u16 family; offset:32; size:2; signed:0; field:__u8 saddr[4]; offset:34; size:4; signed:0; field:__u8 daddr[4]; offset:38; size:4; signed:0; field:__u8 saddr_v6[16]; offset:42; size:16; signed:0; field:__u8 daddr_v6[16]; offset:58; size:16; signed:0; field:int err; offset:76; size:4; signed:1; print fmt: "skbaddr=%p skaddr=%p family=%s sport=%hu dport=%hu saddr=%pI4 daddr=%pI4 saddrv6=%pI6c daddrv6=%pI6c state=%s err=%d" Co-developed-by: xu xin Signed-off-by: xu xin Signed-off-by: Fan Yu Reviewed-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250721111607626_BDnIJB0ywk6FghN63bor@zte.com.cn Signed-off-by: Jakub Kicinski

net/tcp_ao: tracing: Hide tcp_ao events under CONFIG_TCP_AO

2025-06-16T21:58:28Z

Several of the tcp_ao events are only called when CONFIG_TCP_AO is defined. As each event can take up to 5K regardless if they are used or not, it's best not to define them when they are not used. Add #ifdef around these events when they are not used. Signed-off-by: Steven Rostedt (Google) Reviewed-by: Simon Horman Link: https://patch.msgid.link/20250612094616.4222daf0@batman.local.home Signed-off-by: Jakub Kicinski

Merge tag 'trace-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2025-05-30T04:04:36Z

Pull tracing updates from Steven Rostedt: - Have module addresses get updated in the persistent ring buffer The addresses of the modules from the previous boot are saved in the persistent ring buffer. If the same modules are loaded and an address is in the old buffer points to an address that was both saved in the persistent ring buffer and is loaded in memory, shift the address to point to the address that is loaded in memory in the trace event. - Print function names for irqs off and preempt off callsites When ignoring the print fmt of a trace event and just printing the fields directly, have the fields for preempt off and irqs off events still show the function name (via kallsyms) instead of just showing the raw address. - Clean ups of the histogram code The histogram functions saved over 800 bytes on the stack to process events as they come in. Instead, create per-cpu buffers that can hold this information and have a separate location for each context level (thread, softirq, IRQ and NMI). Also add some more comments to the code. - Add "common_comm" field for histograms Add "common_comm" that uses the current->comm as a field in an event histogram and acts like any of the other fields of the event. - Show "subops" in the enabled_functions file When the function graph infrastructure is used, a subsystem has a "subops" that it attaches its callback function to. Instead of the enabled_functions just showing a function calling the function that calls the subops functions, also show the subops functions that will get called for that function too. - Add "copy_trace_marker" option to instances There are cases where an instance is created for tooling to write into, but the old tooling has the top level instance hardcoded into the application. New tools want to consume the data from an instance and not the top level buffer. By adding a copy_trace_marker option, whenever the top instance trace_marker is written into, a copy of it is also written into the instance with this option set. This allows new tools to read what old tools are writing into the top buffer. If this option is cleared by the top instance, then what is written into the trace_marker is not written into the top instance. This is a way to redirect the trace_marker writes into another instance. - Have tracepoints created by DECLARE_TRACE() use trace__tp() If a tracepoint is created by DECLARE_TRACE() instead of TRACE_EVENT(), then it will not be exposed via tracefs. Currently there's no way to differentiate in the kernel the tracepoint functions between those that are exposed via tracefs or not. A calling convention has been made manually to append a "_tp" prefix for events created by DECLARE_TRACE(). Instead of doing this manually, force it so that all DECLARE_TRACE() events have this notation. - Use __string() for task->comm in some sched events Instead of hardcoding the comm to be TASK_COMM_LEN in some of the scheduler events use __string() which makes it dynamic. Note, if these events are parsed by user space it they may break, and the event may have to be converted back to the hardcoded size. - Have function graph "depth" be unsigned to the user Internally to the kernel, the "depth" field of the function graph event is signed due to -1 being used for end of boundary. What actually gets recorded in the event itself is zero or positive. Reflect this to user space by showing "depth" as unsigned int and be consistent across all events. - Allow an arbitrary long CPU string to osnoise_cpus_write() The filtering of which CPUs to write to can exceed 256 bytes. If a machine has 256 CPUs, and the filter is to filter every other CPU, the write would take a string larger than 256 bytes. Instead of using a fixed size buffer on the stack that is 256 bytes, allocate it to handle what is passed in. - Stop having ftrace check the per-cpu data "disabled" flag The "disabled" flag in the data structure passed to most ftrace functions is checked to know if tracing has been disabled or not. This flag was added back in 2008 before the ring buffer had its own way to disable tracing. The "disable" flag is now not always set when needed, and the ring buffer flag should be used in all locations where the disabled is needed. Since the "disable" flag is redundant and incorrect, stop using it. Fix up some locations that use the "disable" flag to use the ring buffer info. - Use a new tracer_tracing_disable/enable() instead of data->disable flag There's a few cases that set the data->disable flag to stop tracing, but this flag is not consistently used. It is also an on/off switch where if a function set it and calls another function that sets it, the called function may incorrectly enable it. Use a new trace_tracing_disable() and tracer_tracing_enable() that uses a counter and can be nested. These use the ring buffer flags which are always checked making the disabling more consistent. - Save the trace clock in the persistent ring buffer Save what clock was used for tracing in the persistent ring buffer and set it back to that clock after a reboot. - Remove unused reference to a per CPU data pointer in mmiotrace functions - Remove unused buffer_page field from trace_array_cpu structure - Remove more strncpy() instances - Other minor clean ups and fixes * tag 'trace-v6.16' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (36 commits) tracing: Fix compilation warning on arm32 tracing: Record trace_clock and recover when reboot tracing/sched: Use __string() instead of fixed lengths for task->comm tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix tracing: Cleanup upper_empty() in pid_list tracing: Allow the top level trace_marker to write into another instances tracing: Add a helper function to handle the dereference arg in verifier tracing: Remove unnecessary "goto out" that simply returns ret is trigger code tracing: Fix error handling in event_trigger_parse() tracing: Rename event_trigger_alloc() to trigger_data_alloc() tracing: Replace deprecated strncpy() with strscpy() for stack_trace_filter_buf tracing: Remove unused buffer_page field from trace_array_cpu structure tracing: Use atomic_inc_return() for updating "disabled" counter in irqsoff tracer tracing: Convert the per CPU "disabled" counter to local from atomic tracing: branch: Use trace_tracing_is_on_cpu() instead of "disabled" field ring-buffer: Add ring_buffer_record_is_on_cpu() tracing: Do not use per CPU array_buffer.data->disabled for cpumask ftrace: Do not disabled function graph based on "disabled" field tracing: kdb: Use tracer_tracing_on/off() instead of setting per CPU disabled tracing: Use tracer_tracing_disable() instead of "disabled" field for ftrace_dump_one() ...

tcp: add tcp_rcvbuf_grow() tracepoint

2025-05-15T18:30:08Z

Provide a new tracepoint to better understand tcp_rcv_space_adjust() (currently broken) behavior. Call it only when tcp_rcv_space_adjust() has a chance to make a change. I chose to leave trace_tcp_rcv_space_adjust() as is, because commit 6163849d289b ("net: introduce a new tracepoint for tcp_rcv_space_adjust") intent was to get it called after each data delivery to user space. Tested: Pair of hosts in the same rack. Ideally, sk->sk_rcvbuf should be kept small. echo "4096 131072 33554432" >/proc/sys/net/ipv4/tcp_rmem ./netserver perf record -C10 -e tcp:tcp_rcvbuf_grow sleep 30 Trace for a TS enabled TCP flow (with standard ms granularity) perf script // We can see that sk_rcvbuf is growing very fast to tcp_mem[2] 260.500397: tcp:tcp_rcvbuf_grow: time=291 rtt_us=274 copied=110592 inq=0 space=41080 ooo=0 scaling_ratio=230 rcvbuf=131072 ... 260.501333: tcp:tcp_rcvbuf_grow: time=555 rtt_us=364 copied=333824 inq=0 space=110592 ooo=0 scaling_ratio=230 rcvbuf=1399144 ... 260.501664: tcp:tcp_rcvbuf_grow: time=331 rtt_us=330 copied=798720 inq=0 space=333824 ooo=0 scaling_ratio=230 rcvbuf=4110551 ... 260.502003: tcp:tcp_rcvbuf_grow: time=340 rtt_us=330 copied=1040384 inq=49152 space=798720 ooo=0 scaling_ratio=230 rcvbuf=7006410 ... 260.502483: tcp:tcp_rcvbuf_grow: time=479 rtt_us=330 copied=2658304 inq=49152 space=1040384 ooo=0 scaling_ratio=230 rcvbuf=7006410 ... 260.502899: tcp:tcp_rcvbuf_grow: time=416 rtt_us=413 copied=4026368 inq=147456 space=2658304 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.504233: tcp:tcp_rcvbuf_grow: time=493 rtt_us=487 copied=4800512 inq=196608 space=4026368 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.504792: tcp:tcp_rcvbuf_grow: time=559 rtt_us=551 copied=5672960 inq=49152 space=4800512 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.506614: tcp:tcp_rcvbuf_grow: time=610 rtt_us=607 copied=6688768 inq=180224 space=5672960 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.507280: tcp:tcp_rcvbuf_grow: time=666 rtt_us=656 copied=6868992 inq=49152 space=6688768 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.507979: tcp:tcp_rcvbuf_grow: time=699 rtt_us=699 copied=7000064 inq=0 space=6868992 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.508681: tcp:tcp_rcvbuf_grow: time=703 rtt_us=699 copied=7208960 inq=0 space=7000064 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.509426: tcp:tcp_rcvbuf_grow: time=744 rtt_us=737 copied=7569408 inq=0 space=7208960 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.510213: tcp:tcp_rcvbuf_grow: time=787 rtt_us=770 copied=7880704 inq=49152 space=7569408 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.511013: tcp:tcp_rcvbuf_grow: time=801 rtt_us=798 copied=8339456 inq=0 space=7880704 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.511860: tcp:tcp_rcvbuf_grow: time=847 rtt_us=824 copied=8601600 inq=49152 space=8339456 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.512710: tcp:tcp_rcvbuf_grow: time=850 rtt_us=846 copied=8814592 inq=65536 space=8601600 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.514428: tcp:tcp_rcvbuf_grow: time=871 rtt_us=865 copied=8855552 inq=49152 space=8814592 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.515333: tcp:tcp_rcvbuf_grow: time=905 rtt_us=882 copied=9228288 inq=49152 space=8855552 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.516237: tcp:tcp_rcvbuf_grow: time=905 rtt_us=896 copied=9371648 inq=49152 space=9228288 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.517149: tcp:tcp_rcvbuf_grow: time=911 rtt_us=909 copied=9543680 inq=49152 space=9371648 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.518070: tcp:tcp_rcvbuf_grow: time=921 rtt_us=921 copied=9793536 inq=0 space=9543680 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.520895: tcp:tcp_rcvbuf_grow: time=948 rtt_us=947 copied=10203136 inq=114688 space=9793536 ooo=0 scaling_ratio=230 rcvbuf=24622616 ... 260.521853: tcp:tcp_rcvbuf_grow: time=959 rtt_us=954 copied=10293248 inq=57344 space=10203136 ooo=0 scaling_ratio=230 rcvbuf=24691992 ... 260.522818: tcp:tcp_rcvbuf_grow: time=964 rtt_us=959 copied=10330112 inq=0 space=10293248 ooo=0 scaling_ratio=230 rcvbuf=24691992 ... 260.524760: tcp:tcp_rcvbuf_grow: time=979 rtt_us=969 copied=10633216 inq=49152 space=10330112 ooo=0 scaling_ratio=230 rcvbuf=24691992 ... 260.526709: tcp:tcp_rcvbuf_grow: time=975 rtt_us=973 copied=12013568 inq=163840 space=10633216 ooo=0 scaling_ratio=230 rcvbuf=25136755 ... 260.527694: tcp:tcp_rcvbuf_grow: time=985 rtt_us=976 copied=12025856 inq=32768 space=12013568 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.530655: tcp:tcp_rcvbuf_grow: time=991 rtt_us=986 copied=12050432 inq=98304 space=12025856 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.533626: tcp:tcp_rcvbuf_grow: time=993 rtt_us=989 copied=12124160 inq=0 space=12050432 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.538606: tcp:tcp_rcvbuf_grow: time=1000 rtt_us=994 copied=12222464 inq=49152 space=12124160 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.545605: tcp:tcp_rcvbuf_grow: time=1005 rtt_us=998 copied=12263424 inq=81920 space=12222464 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.553626: tcp:tcp_rcvbuf_grow: time=1005 rtt_us=999 copied=12320768 inq=12288 space=12263424 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.589749: tcp:tcp_rcvbuf_grow: time=1001 rtt_us=1000 copied=12398592 inq=16384 space=12320768 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 260.806577: tcp:tcp_rcvbuf_grow: time=1010 rtt_us=1000 copied=12402688 inq=32768 space=12398592 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 261.002386: tcp:tcp_rcvbuf_grow: time=1002 rtt_us=1000 copied=12419072 inq=98304 space=12402688 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 261.803432: tcp:tcp_rcvbuf_grow: time=1013 rtt_us=1000 copied=12468224 inq=49152 space=12419072 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 261.829533: tcp:tcp_rcvbuf_grow: time=1004 rtt_us=1000 copied=12615680 inq=0 space=12468224 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... 265.505435: tcp:tcp_rcvbuf_grow: time=1007 rtt_us=1000 copied=12632064 inq=32768 space=12615680 ooo=0 scaling_ratio=230 rcvbuf=33554432 ... We also see rtt_us going gradually to 1000 usec, causing massive overshoot. Trace for a usec TS enabled TCP flow (us granularity) perf script // We can see that sk_rcvbuf is growing to a smaller value, thanks to tight rtt_us values. 1509.273955: tcp:tcp_rcvbuf_grow: time=396 rtt_us=377 copied=110592 inq=0 space=41080 ooo=0 scaling_ratio=230 rcvbuf=131072 ... 1509.274366: tcp:tcp_rcvbuf_grow: time=412 rtt_us=365 copied=129024 inq=0 space=110592 ooo=0 scaling_ratio=230 rcvbuf=1399144 ... 1509.274738: tcp:tcp_rcvbuf_grow: time=372 rtt_us=355 copied=194560 inq=0 space=129024 ooo=0 scaling_ratio=230 rcvbuf=1399144 ... 1509.275020: tcp:tcp_rcvbuf_grow: time=282 rtt_us=257 copied=401408 inq=0 space=194560 ooo=0 scaling_ratio=230 rcvbuf=1399144 ... 1509.275190: tcp:tcp_rcvbuf_grow: time=170 rtt_us=144 copied=741376 inq=229376 space=401408 ooo=0 scaling_ratio=230 rcvbuf=3021625 ... 1509.275300: tcp:tcp_rcvbuf_grow: time=110 rtt_us=110 copied=1146880 inq=65536 space=741376 ooo=0 scaling_ratio=230 rcvbuf=4642390 ... 1509.275449: tcp:tcp_rcvbuf_grow: time=149 rtt_us=106 copied=1310720 inq=737280 space=1146880 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.275560: tcp:tcp_rcvbuf_grow: time=111 rtt_us=107 copied=1388544 inq=430080 space=1310720 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.275674: tcp:tcp_rcvbuf_grow: time=114 rtt_us=113 copied=1495040 inq=421888 space=1388544 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.275800: tcp:tcp_rcvbuf_grow: time=126 rtt_us=126 copied=1572864 inq=77824 space=1495040 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.275968: tcp:tcp_rcvbuf_grow: time=168 rtt_us=161 copied=1863680 inq=172032 space=1572864 ooo=0 scaling_ratio=230 rcvbuf=5498637 ... 1509.276129: tcp:tcp_rcvbuf_grow: time=161 rtt_us=161 copied=1941504 inq=204800 space=1863680 ooo=0 scaling_ratio=230 rcvbuf=5782790 ... 1509.276288: tcp:tcp_rcvbuf_grow: time=159 rtt_us=158 copied=1990656 inq=131072 space=1941504 ooo=0 scaling_ratio=230 rcvbuf=5782790 ... 1509.276900: tcp:tcp_rcvbuf_grow: time=228 rtt_us=226 copied=2883584 inq=266240 space=1990656 ooo=0 scaling_ratio=230 rcvbuf=5782790 ... 1509.277819: tcp:tcp_rcvbuf_grow: time=242 rtt_us=236 copied=3022848 inq=0 space=2883584 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.278072: tcp:tcp_rcvbuf_grow: time=253 rtt_us=247 copied=3055616 inq=49152 space=3022848 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.279560: tcp:tcp_rcvbuf_grow: time=268 rtt_us=264 copied=3133440 inq=180224 space=3055616 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.279833: tcp:tcp_rcvbuf_grow: time=274 rtt_us=270 copied=3424256 inq=0 space=3133440 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.282187: tcp:tcp_rcvbuf_grow: time=277 rtt_us=273 copied=3465216 inq=180224 space=3424256 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.284685: tcp:tcp_rcvbuf_grow: time=292 rtt_us=292 copied=3481600 inq=147456 space=3465216 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.284983: tcp:tcp_rcvbuf_grow: time=297 rtt_us=295 copied=3702784 inq=45056 space=3481600 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.285596: tcp:tcp_rcvbuf_grow: time=311 rtt_us=310 copied=3723264 inq=40960 space=3702784 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.285909: tcp:tcp_rcvbuf_grow: time=313 rtt_us=304 copied=3846144 inq=196608 space=3723264 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.291654: tcp:tcp_rcvbuf_grow: time=322 rtt_us=311 copied=3960832 inq=49152 space=3846144 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.291986: tcp:tcp_rcvbuf_grow: time=333 rtt_us=330 copied=4075520 inq=360448 space=3960832 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.292319: tcp:tcp_rcvbuf_grow: time=332 rtt_us=332 copied=4079616 inq=65536 space=4075520 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.292666: tcp:tcp_rcvbuf_grow: time=348 rtt_us=347 copied=4177920 inq=212992 space=4079616 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.293015: tcp:tcp_rcvbuf_grow: time=349 rtt_us=345 copied=4276224 inq=262144 space=4177920 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.293371: tcp:tcp_rcvbuf_grow: time=356 rtt_us=346 copied=4415488 inq=49152 space=4276224 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... 1509.515798: tcp:tcp_rcvbuf_grow: time=424 rtt_us=411 copied=4833280 inq=81920 space=4415488 ooo=0 scaling_ratio=230 rcvbuf=12316197 ... Signed-off-by: Eric Dumazet Reviewed-by: Wei Wang Reviewed-by: Neal Cardwell Link: https://patch.msgid.link/20250513193919.1089692-2-edumazet@google.com Signed-off-by: Jakub Kicinski

tracepoint: Have tracepoints created with DECLARE_TRACE() have _tp suffix

2025-05-14T15:19:32Z

Most tracepoints in the kernel are created with TRACE_EVENT(). The TRACE_EVENT() macro (and DECLARE_EVENT_CLASS() and DEFINE_EVENT() where in reality, TRACE_EVENT() is just a helper macro that calls those other two macros), will create not only a tracepoint (the function trace_() used in the kernel), it also exposes the tracepoint to user space along with defining what fields will be saved by that tracepoint. There are a few places that tracepoints are created in the kernel that are not exposed to userspace via tracefs. They can only be accessed from code within the kernel. These tracepoints are created with DEFINE_TRACE() Most of these tracepoints end with "_tp". This is useful as when the developer sees that, they know that the tracepoint is for in-kernel only (meaning it can only be accessed inside the kernel, either directly by the kernel or indirectly via modules and BPF programs) and is not exposed to user space. Instead of making this only a process to add "_tp", enforce it by making the DECLARE_TRACE() append the "_tp" suffix to the tracepoint. This requires adding DECLARE_TRACE_EVENT() macros for the TRACE_EVENT() macro to use that keeps the original name. Link: https://lore.kernel.org/all/20250418083351.20a60e64@gandalf.local.home/ Cc: netdev Cc: Jiri Olsa Cc: Peter Zijlstra Cc: David Ahern Cc: Juri Lelli Cc: Breno Leitao Cc: Alexei Starovoitov Cc: Andrii Nakryiko Cc: Gabriele Monaco Cc: Masami Hiramatsu Link: https://lore.kernel.org/20250510163730.092fad5b@gandalf.local.home Acked-by: Mathieu Desnoyers Acked-by: Andrii Nakryiko Signed-off-by: Steven Rostedt (Google)

trace: tcp: Add const qualifier to skb parameter in tcp_probe event

2025-04-18T02:04:43Z

Change the tcp_probe tracepoint to accept a const struct sk_buff parameter instead of a non-const one. This improves type safety and better reflects that the skb is not modified within the tracepoint implementation. Signed-off-by: Breno Leitao Reviewed-by: Kuniyuki Iwashima Link: https://patch.msgid.link/20250416-tcp_probe-v1-1-1edc3c5a1cb8@debian.org Signed-off-by: Jakub Kicinski

trace: tcp: Add tracepoint for tcp_sendmsg_locked()

2025-04-11T01:34:05Z

Add a tracepoint to monitor TCP send operations, enabling detailed visibility into TCP message transmission. Create a new tracepoint within the tcp_sendmsg_locked function, capturing traditional fields along with size_goal, which indicates the optimal data size for a single TCP segment. Additionally, a reference to the struct sock sk is passed, allowing direct access for BPF programs. The implementation is largely based on David's patch[1] and suggestions. Link: https://lore.kernel.org/all/70168c8f-bf52-4279-b4c4-be64527aa1ac@kernel.org/ [1] Signed-off-by: Breno Leitao Reviewed-by: David Ahern Reviewed-by: Kuniyuki Iwashima Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250408-tcpsendmsg-v3-2-208b87064c28@debian.org Signed-off-by: Jakub Kicinski

trace: tcp: Add tracepoint for tcp_cwnd_reduction()

2025-02-18T14:29:53Z

Add a lightweight tracepoint to monitor TCP congestion window adjustments via tcp_cwnd_reduction(). This tracepoint enables tracking of: - TCP window size fluctuations - Active socket behavior - Congestion window reduction events Meta has been using BPF programs to monitor this function for years. Adding a proper tracepoint provides a stable API for all users who need to monitor TCP congestion window behavior. Use DECLARE_TRACE instead of TRACE_EVENT to avoid creating trace event infrastructure and exporting to tracefs, keeping the implementation minimal. (Thanks Steven Rostedt) Given that this patch creates a rawtracepoint, you could hook into it using regular tooling, like bpftrace, using regular rawtracepoint infrastructure, such as: rawtracepoint:tcp_cwnd_reduction_tp { .... } Signed-off-by: Breno Leitao Reviewed-by: Eric Dumazet Link: https://patch.msgid.link/20250214-cwnd_tracepoint-v2-1-ef8d15162d95@debian.org Signed-off-by: Paolo Abeni

tcp: Use skb__nullable in trace_tcp_send_reset

2024-09-11T15:56:42Z

Replace skb with skb__nullable as the argument name. The suffix tells bpf verifier through btf that the arg could be NULL and should be checked in tp_btf prog. For now, this is the only nullable argument in tcp tracepoints. Signed-off-by: Philo Lu Acked-by: Jakub Kicinski Link: https://lore.kernel.org/r/20240911033719.91468-4-lulie@linux.alibaba.com Signed-off-by: Martin KaFai Lau