Messages in this thread | | | Date | Fri, 21 May 1999 19:23:12 -0700 (PDT) | From | Simon Kirby <> | Subject | Re: [2.2.9] performance problem on 100MBit network |
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On Thu, 20 May 1999, Jochen Heuer wrote:
> using 2.2.9 on my server or my client brings down the performance > on my local network. I'm using SMC Etherpower II on both machines > which are connected via a 100MBit hub. > > Using ftp the transferrates drop to ~200 k/s (>6 M/s with 2.2.8). > If I revert the following part of patch-2.2.9 the network runs at > full speed again: > > diff -u --recursive --new-file v2.2.8/linux/include/net/tcp.h linux/include/net/tcp.h > --- v2.2.8/linux/include/net/tcp.h Tue May 11 13:10:32 1999 > +++ linux/include/net/tcp.h Thu May 13 10:33:17 1999 > @@ -728,7 +728,7 @@ > */ > extern __inline__ __u32 tcp_recalc_ssthresh(struct tcp_opt *tp) > { > - __u32 snd_wnd_packets = tp->snd_wnd / tp->mss_cache; > + __u32 snd_wnd_packets = tp->snd_wnd / max(tp->mss_cache, 1); > > return max(min(snd_wnd_packets, tp->snd_cwnd) >> 1, 2); > } > > > What is the reason behind this patch or can I tune my system > using /proc/sys/net ?
This cannot be possible unless a compiler is breaking something here. What you are reverting avoids a possible division by zero -- the only way it could have been faster before was if it was spitting out divison by zero errors and still going. Are you changing anything else between kernels?
Simon-
| Simon Kirby | Systems Administration | | mailto:sim@netnation.com | NetNation Communications | | http://www.netnation.com/ | Tech: (604) 684-6892 |
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