- From: <touch@ISI.EDU>
- Date: Wed, 29 Nov 1995 15:34:36 -0800
- To: marc@ckm.ucsf.edu
- Cc: www-talk@www0.cern.ch, www-speed@tipper.oit.unc.edu, www-html@www0.cern.ch
> From: "Marc Salomon" <marc@matahari.ckm.ucsf.edu> > Date: Wed, 29 Nov 1995 14:47:28 -0800 > To: touch@ISI.EDU > Subject: Re: two ideas... > > |We found that server speculation would decrease latency by 2/3, to 0.7 > |RTT (yes, below the speed of light) by increasing the BW by 7x. Note > |that this RTT is an average per page - it still takes 1 RTT for the > |first page... > > But do these speculative pre-fetch schemes scale? To answer that I would ask > what is the ratio of the number of unused prefetched pages to number of > pre-fetches total? > > -marc They scale, but not how you'd like. Adding BW has a logarithmic effect on latency reduction, but only within the tree of HTML from a single source. I don't have statistics on how long users stay at a source - that's client-side logging info, whereas web servers (by nature) log server-side stuff only. I would predict that they would scale to around BW = 7^3, or around 350x, and latency would reduce from 2.1 RTT's down to 0.2 RTTs avg per request. The real goal question is: what is the min BW required to support interactive web access? this depends on whether you support HTML/ASCII, icons (small gifs), screen images (gifs), or higher resolution stuff... PS - the Lowlat pages now have the graph that describes this. PPS - this seemed like a general enough question, I thought I'd share the response with www-speed - I hope that's OK.. Joe
Received on Wednesday, 29 November 1995 18:37:53 UTC