Messages in this thread Patch in this message | | | Date | Fri, 26 Feb 1999 18:18:25 +0100 (CET) | From | Andrea Arcangeli <> | Subject | Re: Linux 2.2.2 TCP delays every 41st small packet by 10-20 ms |
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On Thu, 25 Feb 1999, Josip Loncaric wrote:
>The conclusion is this: in Linux TCP, every N-th small packet is delayed >by 1-2 "jiffies" (defined by the 100 Hz system clock). For Linux kernel
This 1-2 jiffies made me thing again at the PSH thing. Probably I am completly out but could you try this patch?
Index: tcp_input.c =================================================================== RCS file: /var/cvs/linux/net/ipv4/tcp_input.c,v retrieving revision 1.1.2.13 diff -u -r1.1.2.13 tcp_input.c --- tcp_input.c 1999/02/26 17:39:46 1.1.2.13 +++ linux/net/ipv4/tcp_input.c 1999/02/26 17:40:14 @@ -55,6 +55,7 @@ * work without delayed acks. * Andi Kleen: Process packets with PSH set in the * fast path. + * Andrea Arcangeli: Quickack if received a tiny PSH packet. */ #include <linux/config.h> @@ -133,12 +134,8 @@ /* Tiny-grams with PSH set artifically deflate our * ato measurement, but with a lower bound. */ - if(th->psh && (skb->len < (tp->mss_cache >> 1))) { - /* Preserve the quickack state. */ - if((tp->ato & 0x7fffffff) > HZ/50) - tp->ato = ((tp->ato & 0x80000000) | - (HZ/50)); - } + if(th->psh && (skb->len < (tp->mss_cache >> 1))) + tcp_enter_quickack_mode(tp); } /* Called to compute a smoothed rtt estimate. The data fed to this
Andrea Arcangeli
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