igodard

6 ms·

1.
by igodard 9y ago
Much of the Mill is not new; we don't bother filing those parts. Much that is not new is very good, and was abandoned for reasons unrelated to the actual merits. The first compiler I ever wrote was for the Burroughs B6500, which in 197
2.
by igodard 9y ago
The grant model requires you to grant each object individually that you want to pass. That is annoying if you have many objects. In both the caps and grant models you can cut the overhead by thinking of the whole graph as "the object&q
3.
by igodard 9y ago
There are dededicated Well-Known-Regions for code, stack, globals and TLS that catch the great majority of memory references. The PLB is only consulted when we miss in the WKRs. What's not in the WKRs? MAP_SHARED mmap()s. How many of t
4.
by igodard 9y ago
The tool chain does hoisting and if-conversion with wild abandon. That code becomes {x = cond ? a+b : a*b}, and both expressions are evaluated in parallel. The conversion is a heuristic; if you have tracing data for the branch then it might
5.
by igodard 9y ago
We have focused on the core and less on the uncore, which is why there have been no talks on I/O. The goal is for a smart peripheral to be indistinguishable from just another regular core; the Mill design is big on regularity. That imp
6.
by igodard 9y ago
That's really more the VC model; a bootstrap is different.
7.
by igodard 9y ago
Caution is always warranted when you aren't getting cash on the barrel. The sweat equity documents are available - ask on the site (and now that I think about it, I suppose we should just put them on the site directly). There's no
8.
by igodard 9y ago
So would we. See millcomputing.com -> About -> Invest in Us.
9.
by igodard 9y ago
All sound points. Most of what you'd like to see are things we'd like to see too. At the beginning we decided to bootstrap rather than follow the usual funding model, at least to the point at which we could demonstrate what we had
10.
by igodard 9y ago
The Mill grant-based model is semantically quite similar to capabilities, but it associates protection with the accessor (thread/turf) rather than the access (pointer/capability). This lets us preserve the size of a pointer, which
11.
by igodard 9y ago
>Unless there's something else not mentioned in the talk, it seems like you still need to trust the OS, because when the OS is asked to allocate a page for a spillet there is nothing stopping it from creating a virtual alias of that
12.
by igodard 9y ago
No, it's aliasing, just as any fork() is. COW lowers the cost, for Mill as for any other. The Mill fork duplicates the address space, not the memory. The memory is duplicated page by page on demand, i.e. copy-on-write. Mill paging is q
13.
by igodard 9y ago
The biggest problem with caps and legacy apps is not the semantics - a caps systems can emulate POSIX with no problem. The problem is the data representation: you can't fit a capability into a pointer, so all the data layouts change. S
14.
by igodard 9y ago
The next talk will be on threading, and will address all this. The IPC and threads talks belong together, but are too big to combine in one talk unfortunately.
15.
by igodard 9y ago
Mill has no register file, and is essentially a bypass network internally. That bypass network has a source X sink complexity (not N^2 because the number of sources need not match the number of sinks). You are right that the cross product i
16.
by igodard 9y ago
The target is not static; it is dynamically updated as part of history. Prefetch chaining is to get code out of DRAM, and it runs DRAM-latency ahead of execution. Separately, fetch chaining is to get the code up to the L1, and it runs L2&#x
17.
by igodard 9y ago
Perhaps you could revisit the prediction talk. Short summary: Table reload is part of our support for the micro-process coding style. It is essentially irrelevant for typical long running benchmarks, especially those that discard the first
18.
by igodard 10y ago
Such paranoia is amply justified in our industry. However I expect that we will continue our iconoclastic approach to legalisms so long as the founders keep control. Our model for our cloud software follows the example pioneered by Greg Com
19.
by igodard 10y ago
A more likely strategy for a major (not Intel specifically) is to just use whatever they want without a license, and beat us to death with lawyers.
20.
by igodard 10y ago
You show your age :-)
21.
by igodard 10y ago
Yes
22.
by igodard 10y ago
Those issues are pretty easy. For spilling: if a desired argument is less than one belt-length away then we directly reference it; between one and two away we reorder; and more than two we spill. We place a load as soon as the address argum
23.
by igodard 10y ago
Optimal register coloring is NP hard, but no compiler does that; heuristics are no worse than quadratic and give near-optimal. The Mill specializer part that schedules ops is linear, while the part that assigns belt numbers and inserts spil
24.
by igodard 10y ago
Yes - by those with established businesses. I can't think of a startup that succeeded with an initial incremental, at lease since Amdahl. It's also hard to do an increment: the Intel teams are not dumb, and many could and have bui
25.
by igodard 10y ago
Judge us on the tech, not on me. To be honest, if you cannot already understand what we have put out to the public well enough to know that you want to work on it, then you are probably still too junior to be really useful as we are now. We
26.
by igodard 10y ago
See https://millcomputing.com/#JoinUs NDA and sweat-equity agreement required; you get full-vested long-term options monthly; expected to be actual stock monthly after the next round. To help in a FOSS context: we are not y
27.
by igodard 10y ago
All but #4. Our business model is to sell chips, not licenses. Why? Intel's quarterly dividend is bigger than ARM's annual revenue. Licensing is a backup plan.
28.
by igodard 10y ago
Our industry is a surprisingly small pond, at the top anyway. No one would invest in the Mill based on my formal bio "College dropout; never took a CS course in his life" :-) Instead they invest based on our technology, most of wh
29.
by igodard 10y ago
Both. Both full- and part-timers are on sweat-equity, no cash, although we will be switching to cash-optional with the next funding round.
30.
by igodard 10y ago
GenAsm for the factorial function (conAsm in a different reply, above): define external function @fact w (in w) locals($3, %9, &0, ^6) { label $0: %1 = sub(%0, 1) ^0; %2 = gtrsb(%1, 1) ^1; br(%2, $1, $2); label $1 dom

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