From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Eric Dumazet <edumazet@google.com>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>,
Kuniyuki Iwashima <kuniyu@google.com>,
Willem de Bruijn <willemb@google.com>,
netdev@vger.kernel.org, eric.dumazet@gmail.com,
Eric Dumazet <edumazet@google.com>
Subject: Re: [PATCH net-next] net: use ktime_t in struct scm_timestamping_internal
Date: Tue, 03 Mar 2026 22:26:06 -0500 [thread overview]
Message-ID: <willemdebruijn.kernel.24c9a9b9e12df@gmail.com> (raw)
In-Reply-To: <20260304012747.881644-1-edumazet@google.com>
Eric Dumazet wrote:
> Instead of using struct timespec64 in scm_timestamping_internal,
> use ktime_t, saving 24 bytes in kernel stack.
>
> This makes tcp_update_recv_tstamps() small enough to be inlined.
>
> The ktime_t -> timespec64 conversions happen after socket lock
> has been released in tcp_recvmsg(), and only if the application
> requested them.
>
> $ scripts/bloat-o-meter -t vmlinux.0 vmlinux
> add/remove: 0/2 grow/shrink: 5/4 up/down: 146/-277 (-131)
> Function old new delta
> tcp_zerocopy_receive 2383 2425 +42
> mptcp_recvmsg 1565 1607 +42
> tcp_recvmsg_locked 3797 3823 +26
> put_cmsg_scm_timestamping64 131 149 +18
> put_cmsg_scm_timestamping 131 149 +18
> __pfx_tcp_update_recv_tstamps 16 - -16
> do_tcp_getsockopt 4024 4006 -18
> tcp_recv_timestamp 474 430 -44
> tcp_zc_handle_leftover 417 371 -46
> __sock_recv_timestamp 1087 1031 -56
> tcp_update_recv_tstamps 97 - -97
> Total: Before=25223788, After=25223657, chg -0.00%
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
next prev parent reply other threads:[~2026-03-04 3:26 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-04 1:27 [PATCH net-next] net: use ktime_t in struct scm_timestamping_internal Eric Dumazet
2026-03-04 3:26 ` Willem de Bruijn [this message]
2026-03-04 7:11 ` Jason Xing
2026-03-05 2:56 ` Eric Dumazet
2026-03-05 2:40 ` patchwork-bot+netdevbpf
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