Commit 4b78c9cb authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

tcp: move tp->chrono_type next tp->chrono_stat[] 



chrono_type is currently in tcp_sock_read_txrx group, which
is supposed to hold read-mostly fields.

But chrono_type is mostly written in tx path, it should
be moved to tcp_sock_write_tx group, close to other
chrono fields (chrono_stat[], chrono_start).

Note this adds holes, but data locality is far more important.

Use a full u8 for the time being, compiler can generate
more efficient code.

Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarNeal Cardwell <ncardwell@google.com>
Link: https://patch.msgid.link/20260308122302.2895067-1-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent f2db7b80

include/linux/tcp.h

+2 −2
Original line number Diff line number Diff line
@@ -228,8 +228,7 @@ struct tcp_sock { 
	u32	sacked_out;	/* SACK'd packets			*/

	u16	tcp_header_len;	/* Bytes of tcp header to send		*/

	u8	scaling_ratio;	/* see tcp_win_from_space() */

	u8	chrono_type : 2,	/* current chronograph type */

		repair      : 1,

	u8	repair      : 1,

		tcp_usec_ts : 1, /* TSval values in usec */

		is_sack_reneg:1,    /* in recovery from loss with SACK reneg? */

		is_cwnd_limited:1,/* forward progress limited by snd_cwnd? */
@@ -264,6 +263,7 @@ struct tcp_sock { 
				 * total number of data bytes sent.

				 */

	u32	snd_sml;	/* Last byte of the most recently transmitted small packet */

	u8	chrono_type;	/* current chronograph type */

	u32	chrono_start;	/* Start time in jiffies of a TCP chrono */

	u32	chrono_stat[3];	/* Time in jiffies for chrono_stat stats */

	u32	write_seq;	/* Tail(+1) of data held in tcp send buffer */