Re: [PATCH net v3 2/4] trace: tcp: add three metrics to trace_tcp_rcvbuf_grow()

[Neal Cardwell]

On Tue, Oct 28, 2025 at 7:58 AM Matthieu Baerts (NGI0)
<matttbe@xxxxxxxxxx> wrote:
>
> From: Eric Dumazet <edumazet@xxxxxxxxxx>
>
> 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 <edumazet@xxxxxxxxxx>
> Signed-off-by: Matthieu Baerts (NGI0) <matttbe@xxxxxxxxxx>
> ---

Reviewed-by: Neal Cardwell <ncardwell@xxxxxxxxxx>

Thanks, Eric and Matthieu!

neal