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From: Shakeel Butt <shakeelb@google.com>
To: Coco Li <lixiaoyan@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>,
	Eric Dumazet <edumazet@google.com>,
	 Neal Cardwell <ncardwell@google.com>,
	Mubashir Adnan Qureshi <mubashirq@google.com>,
	 Paolo Abeni <pabeni@redhat.com>, Andrew Lunn <andrew@lunn.ch>,
	Jonathan Corbet <corbet@lwn.net>,
	 David Ahern <dsahern@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	netdev@vger.kernel.org,  Chao Wu <wwchao@google.com>,
	Wei Wang <weiwan@google.com>,
	 Pradeep Nemavat <pnemavat@google.com>
Subject: Re: [PATCH v8 net-next 1/5] Documentations: Analyze heavily used Networking related structs
Date: Sat, 2 Dec 2023 20:00:56 +0000	[thread overview]
Message-ID: <20231202195922.a3ekbrdfgqzfm6al@google.com> (raw)
In-Reply-To: <20231129072756.3684495-2-lixiaoyan@google.com>

On Wed, Nov 29, 2023 at 07:27:52AM +0000, Coco Li wrote:
> Analyzed a few structs in the networking stack by looking at variables
> within them that are used in the TCP/IP fast path.
> 
> Fast path is defined as TCP path where data is transferred from sender to
> receiver unidirectionally. It doesn't include phases other than
> TCP_ESTABLISHED, nor does it look at error paths.
> 
> We hope to re-organizing 

We plan to reorganize?

> variables that span many cachelines whose fast
> path variables are also spread out, and this document can help future
> developers keep networking fast path cachelines small.
> 
> Optimized_cacheline field is computed as
> (Fastpath_Bytes/L3_cacheline_size_x86), and not the actual organized
> results (see patches to come for these).
> 
> Investigation is done on 6.5
> 
> Name	                Struct_Cachelines  Cur_fastpath_cache Fastpath_Bytes Optimized_cacheline
> tcp_sock	        42 (2664 Bytes)	   12   		396		8
> net_device	        39 (2240 bytes)	   12			234		4
> inet_sock	        15 (960 bytes)	   14			922		14
> Inet_connection_sock	22 (1368 bytes)	   18			1166		18
> Netns_ipv4 (sysctls)	12 (768 bytes)     4			77		2
> linux_mib	        16 (1060)	   6			104		2
> 

Is there any hidden meaning behind the capital I and N for
Inet_connection_sock and Netns_ipv4?

> Note how there isn't much improvement space for inet_sock and
> Inet_connection_sock because sk and icsk_inet respectively takes up so
> much of the struct that rest of the variables become a small portion of
> the struct size.
> 
> So, we decided to reorganize tcp_sock, net_device, netns_ipv4
> 
> Suggested-by: Eric Dumazet <edumazet@google.com>
> Signed-off-by: Coco Li <lixiaoyan@google.com>

Reviewed-by: Shakeel Butt <shakeelb@google.com>

This is really awesome work and motivated me to do something similar for
struct mem_cgroup (and or mm structs) as well.


  parent reply	other threads:[~2023-12-02 20:00 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-11-29  7:27 [PATCH v8 net-next 0/5] Analyze and Reorganize core Networking Structs to optimize cacheline consumption Coco Li
2023-11-29  7:27 ` [PATCH v8 net-next 1/5] Documentations: Analyze heavily used Networking related structs Coco Li
2023-11-30 10:37   ` Eric Dumazet
2023-12-02 20:00   ` Shakeel Butt [this message]
2023-11-29  7:27 ` [PATCH v8 net-next 2/5] cache: enforce cache groups Coco Li
2023-11-30 10:40   ` Eric Dumazet
2023-12-02  4:20   ` Jakub Kicinski
2023-12-02 20:08   ` Shakeel Butt
2023-11-29  7:27 ` [PATCH v8 net-next 3/5] netns-ipv4: reorganize netns_ipv4 fast path variables Coco Li
2023-11-30 10:48   ` Eric Dumazet
2023-12-02 20:23   ` Shakeel Butt
2023-11-29  7:27 ` [PATCH v8 net-next 4/5] net-device: reorganize net_device " Coco Li
2023-11-30 10:49   ` Eric Dumazet
2023-12-02 20:28   ` Shakeel Butt
2023-11-29  7:27 ` [PATCH v8 net-next 5/5] tcp: reorganize tcp_sock " Coco Li
2023-11-30 10:52   ` Eric Dumazet
2023-12-02 20:31   ` Shakeel Butt
2023-12-02 20:34 ` [PATCH v8 net-next 0/5] Analyze and Reorganize core Networking Structs to optimize cacheline consumption Shakeel Butt
2023-12-02 22:30 ` patchwork-bot+netdevbpf
2023-12-02 22:36   ` Neal Cardwell
2023-12-04 19:06     ` Jakub Kicinski

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