netdev - RE: [PATCH] tcp: disable tcp_autocorking for socket when TCP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20231213213006.89142-1-dipiets@amazon.com>
Date: Wed, 13 Dec 2023 13:30:06 -0800
From: Salvatore Dipietro <dipiets@...zon.com>
To: <edumazet@...gle.com>
CC: <alisaidi@...zon.com>, <benh@...zon.com>, <blakgeof@...zon.com>,
	<davem@...emloft.net>, <dipietro.salvatore@...il.com>, <dipiets@...zon.com>,
	<dsahern@...nel.org>, <kuba@...nel.org>, <netdev@...r.kernel.org>,
	<pabeni@...hat.com>
Subject: RE: [PATCH] tcp: disable tcp_autocorking for socket when TCP_NODELAY flag is set

> It looks like the above disables autocorking even after the userspace
> sets TCP_CORK. Am I reading it correctly? Is that expected?

I have tested a new version of the patch which can target only TCP_NODELAY.
Results using previous benchmark are identical. I will submit it in a new 
patch version.

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -716,7 +716,8 @@

        tcp_mark_urg(tp, flags);

-       if (tcp_should_autocork(sk, skb, size_goal)) {
+       if (!(nonagle & TCP_NAGLE_OFF) &&
+           tcp_should_autocork(sk, skb, size_goal)) {

                /* avoid atomic op if TSQ_THROTTLED bit is already set */
                if (!test_bit(TSQ_THROTTLED, &sk->sk_tsq_flags)) {



> Also I wonder about these 40ms delays, TCP small queue handler should
> kick when the prior skb is TX completed.
>
> It seems the issue is on the driver side ?
>
> Salvatore, which driver are you using ?

I am using ENA driver.

Eric can you please clarify where do you think the problem is?