Re: pipeline_prefetch directive
Amos Jeffries <[email protected]>
| Newsgroups | gmane.comp.web.squid.general |
|---|---|
| Message-ID | <[email protected]> |
On 3/01/25 21:23, Jonathan Lee wrote: > Hello fellow Squid Users, > > I understand this directive is removed in Squid7 again I am still trying to understand more about what it did and does in the older versions of software. > It was an attempt to implement the pipeline mechanism of HTTP/1.1 see <https://httpwg.org/specs/rfc9112.html#pipelining> FYI; very few people have even considered turning it on. So do not be surprised if you do not get a response to your more detailed questions about its behaviour in current Squid. > pipeline_prefetch historically was on or off for settings however today it is n+1 or a numerical value for the variable n. > > My question is after many trial and errors what is a good range to use for a 4GB memory system, > > I have attempted many different n values some being 100, 200, 300, 5, 10 etc it appears to work well with 100 or maybe it was my other changes with > using the directive read_ahead_gap 64 KB and testing 16 and 32 > > what is a good solid go go juice number for pipeline_prefetch? I do notice massive increases in facebook loads when I have it at 100 however decreased performance with news websites. It is like a can’t win directive for me. Finally I thought best to ask. > IMO the answer to that depends on your proxy traffic. * A server that is able to produce responses very fast, operating over a long-delay connection can benefit from requests being sent in a pipeline. * As can two proxies communicating over a multiplexed, fast, **and** reliable connection. Most situations risk adding what is called Head-Of-Line (HOL) blocking delays for the pipelined requests. HTTP/2 was created to solve that problem and does far better. > I do understand it is no longer recommended to be used this is simply for speed and the system is secure behind a firewall. > Firewall existence and security are not relevant to pipeline_prefetch. Pipeline as implemented by Squid is only of much benefit when you already have a high speed situation. As mentioned above. The primary use-case of Squid pipeline_prefetch to my knowledge was for the cache_peer links on proxies acting as accelerators on either end of a geosync satellite communication link. Servicing international level traffic relay for military outposts or small(ish) national teleco's. The primary factor being very long-distance / high-lag TCP links. Cheers Amos _______________________________________________ squid-users mailing list [email protected] https://lists.squid-cache.org/listinfo/squid-users