Re: [9fans] zero copy & 9p (was Re: PDP11 (Was: Re: what heavy negativity!)

2018-10-15 Thread erik quanstrom
> It's useful internally in protocol implementation, specifically to avoid > copying in transport protocols (for later retransmission), and the > modifications aren't vast. > A few changes were trickier, often because of small bugs in the original > code. icmp does some odd things i think. that

Re: [9fans] zero copy & 9p (was Re: PDP11 (Was: Re: what heavy negativity!)

2018-10-15 Thread Charles Forsyth
They are machines designed to run programs most people do not write! On Mon, 15 Oct 2018 at 19:20, hiro <23h...@gmail.com> wrote: > > Also, NUMA effects are more important in practice on big multicores. Some > > of the off-chip delays are brutal. > > yeah, we've been talking about this on

Re: [9fans] zero copy & 9p (was Re: PDP11 (Was: Re: what heavy negativity!)

2018-10-15 Thread hiro
> Also, NUMA effects are more important in practice on big multicores. Some > of the off-chip delays are brutal. yeah, we've been talking about this on #cat-v. even inside one CPU package amd puts multiple dies nowadays, and the cross-die cpu cache access delays are approaching the same

Re: [9fans] zero copy & 9p (was Re: PDP11 (Was: Re: what heavy negativity!)

2018-10-15 Thread hiro
> Btw, "zero copy" isn't the right term and I preferred another term that I've > now forgotten. Minimal copying, perhaps. I like that, "zero-copy" makes me imply other linux-specifics, and those are hard to not get emotional about.

Re: [9fans] zero copy & 9p (was Re: PDP11 (Was: Re: what heavy negativity!)

2018-10-15 Thread Charles Forsyth
It's useful internally in protocol implementation, specifically to avoid copying in transport protocols (for later retransmission), and the modifications aren't vast. A few changes were trickier, often because of small bugs in the original code. icmp does some odd things i think. Btw, "zero copy"

Re: [9fans] PDP11 (Was: Re: what heavy negativity!)

2018-10-15 Thread Giacomo Tesio
Il giorno dom 14 ott 2018 alle ore 19:39 Ole-Hjalmar Kristensen ha scritto: > > OK, that makes sense. So it would not stop a client from for example first > read an index block in a B-tree, wait for the result, and then issue read > operations for all the data blocks in parallel. If the client