On 04/16/2018 08:33 AM, Yafang Shao wrote:
> tcp_rcv_space_adjust is called every time data is copied to user space,
> introducing a tcp tracepoint for which could show us when the packet is
> copied to user.
> This could help us figure out whether there's latency in user process.
> When a tcp packet arrives, tcp_rcv_established() will be called and with
> the existed tracepoint tcp_probe we could get the time when this packet
> Then this packet will be copied to user, and tcp_rcv_space_adjust will
> be called and with this new introduced tracepoint we could get the time
> when this packet is copied to user.
> arrives time : user process time => latency caused by user
> tcp_probe tcp_rcv_space_adjust
> Hence in the prink message, sk is printed as a key to connect these two
socket pointer is not a key.
TCP sockets can be reused pretty fast after free.
I suggest you go for cookie instead, this is an unique 64bit identifier.
( sock_gen_cookie() for details )