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

2018-10-10 Thread erik quanstrom
I have been able to copy 1 GiB/s to userspace from an nvme device.  I should think a radio should be no problem.- Erik

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

2018-10-10 Thread Bakul Shah
On Oct 9, 2018, at 3:06 PM, erik quanstrom wrote: > > with meltdown/Spectre mitigations in place, I would like to see evidence that > flip is faster than copy. If your system is well balanced, you should be able to stream data as fast as memory allows[1]. In such a system copying things N

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

2018-10-10 Thread erik quanstrom
zero copy is also the source of the dreaded 'D' state.- Erik

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

2018-10-10 Thread Giacomo Tesio
Il giorno mar 9 ott 2018 alle ore 05:33 Lucio De Re ha scritto: > > On 10/9/18, Bakul Shah wrote: > > > > One thing I have mused about is recasting plan9 as a > > microkernel and pushing out a lot of its kernel code into user > > mode code. It is already half way there -- it is basically a > >

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

2018-10-10 Thread Digby R.S. Tarvin
I don't know which other ARM board you tried, but I have always found terrible I/O performance of the Pi to be a bigger problem that the ARM speed. The USB2 interface is really slow, and there arn't really many other (documented) alternative options. The Ethernet goes through the same slow USB

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

2018-10-10 Thread hiro
I agree, if you have a choice avoid rpi by all costs. Even if the software side of that other board was less pleasent at least it worked with my mouse and keyboard!! :) As I said I was looking at 2Mbit/s stuff, which is nothing, even over USB. But my point is that even though this number is low,

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

2018-10-10 Thread Ethan Gardener
On Tue, Oct 9, 2018, at 11:22 PM, Digby R.S. Tarvin wrote: > > > On Tue, 9 Oct 2018 at 23:00, Ethan Gardener wrote: >> >> Fascinating thread, but I think you're off by a decade with the 16-bit >> address bus comment, unless you're not actually talking about Plan 9.  The >> 8086 and 8088 were

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

2018-10-10 Thread Steve Simon
people come down very hard on the pi. here are my times for building the pi kernel. i rebuilt it a few times to push data into any caches available. pi3+ with a high-ish spec sd card: 23 secs dual intel atom 1.8Ghz with an SSD: 9 secs the pi is slower, but not 10 times slower. However it

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

2018-10-10 Thread erik quanstrom
> > with meltdown/Spectre mitigations in place, I would like to see evidence > > that flip is faster than copy. > > If your system is well balanced, you should be able to > stream data as fast as memory allows[1]. In such a system > copying things N times will reduce throughput by similar >

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

2018-10-10 Thread cinap_lenrek
oh! you wrote a nvme driver TOO? where can i find it? maybe we can share some knowledge. especially regarding some quirks. i dont own hardware myself, so i wrote it using an emulator over a weekend and tested it on a work machine afterwork.

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

2018-10-10 Thread cinap_lenrek
> But the reason I want this is to reduce latency to the first > access, especially for very large files. With read() I have > to wait until the read completes. With mmap() processing can > start much earlier and can be interleaved with background > data fetch or prefetch. With read() a lot more

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

2018-10-10 Thread Ethan Gardener
On Tue, Oct 9, 2018, at 8:14 PM, Lyndon Nerenberg wrote: > hiro writes: > > > Huh? What exactly do you mean? Can you describe the scenario and the > > measurements you made? > > The big one is USB. disk/radio->kernel->user-space-usbd->kernel->application. > Four copies. > > I would like to

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

2018-10-10 Thread Digby R.S. Tarvin
Well, I think 'avoid at all costs' is a bit strong. The Raspberry Pi is a good little platform for the right applications, so long as you are aware of its limitations. I use one as my 'always on' home server to give me access files when travelling (the networking is slow by LAN standards, but ok

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

2018-10-10 Thread Skip Tavakkolian
For operations that matter in this context (read, write), there can be multiple outstanding tags. A while back rsc implemented fcp, partly to prove this point. On Wed, Oct 10, 2018 at 2:54 PM Steven Stallion wrote: > As the guy who wrote the majority of the code that pushed those 1M 4K > random

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

2018-10-10 Thread Kurt H Maier
On Wed, Oct 10, 2018 at 04:54:22PM -0500, Steven Stallion wrote: > As the guy might be worth keeping in mind the current most common use case for nvme is laptop storage and not building jet engines in coraid's basement so the nvme driver that cinap wrote works on my thinkpad today and is about

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

2018-10-10 Thread Steven Stallion
> On Oct 10, 2018, at 2:54 PM, Steven Stallion wrote: > > You seem to be saying zero-copy wouldn't buy anything until these > other problems are solved, right? Fundamentally zero-copy requires that the kernel and user process share the same virtual address space mapped for the given operation.

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

2018-10-10 Thread Steven Stallion
As the guy who wrote the majority of the code that pushed those 1M 4K random IOPS erik mentioned, this thread annoys the shit out of me. You don't get an award for writing a driver. In fact, it's probably better not to be known at all considering the bloody murder one has to commit to marry

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

2018-10-10 Thread cinap_lenrek
> Fundamentally zero-copy requires that the kernel and user process > share the same virtual address space mapped for the given operation. and it is. this doesnt make your point clear. the kernel is always mapped. (you ment 1:1 identity mapping *PHYSICAL* pages to make the lookup cheap?) the

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

2018-10-10 Thread Dan Cross
On Wed, Oct 10, 2018 at 7:58 PM wrote: > > Fundamentally zero-copy requires that the kernel and user process > > share the same virtual address space mapped for the given operation. > > and it is. this doesnt make your point clear. the kernel is always mapped. > Meltdown has shown this to be a

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

2018-10-10 Thread cinap_lenrek
hahahahahahahaha -- cinap

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

2018-10-10 Thread Bakul Shah
Excellent response! Just what I was hoping for! On Oct 10, 2018, at 2:54 PM, Steven Stallion wrote: > > As the guy who wrote the majority of the code that pushed those 1M 4K > random IOPS erik mentioned, this thread annoys the shit out of me. You > don't get an award for writing a driver. In

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

2018-10-10 Thread Steven Stallion
Posted August 15th, 2013: https://9p.io/sources/contrib/stallion/src/sdmpt2.c Corresponding announcement: https://groups.google.com/forum/#!topic/comp.os.plan9/134-YyYnfbQ On Wed, Oct 10, 2018 at 5:31 PM Kurt H Maier wrote: > > On Wed, Oct 10, 2018 at 04:54:22PM -0500, Steven Stallion wrote: > >

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

2018-10-10 Thread Digby R.S. Tarvin
On Wed, 10 Oct 2018 at 21:40, Ethan Gardener wrote: > > > > Not sure I would agree with that. The 20 bit addressing of the 8086 and > 8088 did not change their 16 bit nature. They were still 16 bit program > counter, with segmentation to provide access to a larger memory - similar > in principle

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

2018-10-10 Thread Steven Stallion
Interesting - was this ever generalized? It's been several years since I last looked, but I seem to recall that unless you went out of your way to write your own 9P implementation, you were limited to a single tag. On Wed, Oct 10, 2018 at 7:51 PM Skip Tavakkolian wrote: > > For operations that

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

2018-10-10 Thread Bakul Shah
On Wed, 10 Oct 2018 20:56:20 -0400 Dan Cross wrote: > > On Wed, Oct 10, 2018 at 7:58 PM wrote: > > > > Fundamentally zero-copy requires that the kernel and user process > > > share the same virtual address space mapped for the given operation. > > > > and it is. this doesnt make your point

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

2018-10-10 Thread Steven Stallion
On Wed, Oct 10, 2018 at 9:32 PM Bakul Shah wrote: > Steve wrote "1:1 mapping of the virtual kernel address space such > that something like zero-copy could be possible" > > Not sure what he meant. For zero copy you need to *directly* > write to the memory allocated to a process. 1:1 mapping is >

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

2018-10-10 Thread Steven Stallion
On Wed, Oct 10, 2018 at 8:20 PM Dan Cross wrote: >> don't forget the code complexity with dealing with these scattered >> pages in the *DRIVERS*. > > It's really not that hard. The way Linux does it is pretty bad, but it's not > like that's the only way to do it. SunOS and Win32 (believe it or