flop | Go file operations library chasing GNU APIs

1 FP operation per core clock cycle would be pathetic for a modern superscalar CPU. Your Skylake-derived CPU can actually do 2x 4-wide SIMD double-precision FMA operations per core per clock, and each FMA counts as two FLOPs, so theoretical max = 16 double-precision FLOPs per core clock, so 24 * 16 = 384 GFLOP/S. (Using vectors of 4 doubles, i.e. 256-bit wide AVX). See FLOPS per cycle for sandy-bridge and haswell SSE2/AVX/AVX2

There is a a function call inside the timed region, callq 403c0b <_Z12do_timed_runRKmRd+0x1eb> (as well as the __kmpc_end_serialized_parallel stuff).

There's no symbol associated with that call target, so I guess you didn't compile with debug info enabled. (That's separate from optimization level, e.g. gcc -g -O3 -march=native -fopenmp should run the same asm, just have more debug metadata.) Even a function invented by OpenMP should have a symbol name associated at some point.

As far as benchmark validity, a good litmus test is whether it scales reasonably with problem size. Unless you exceed L3 cache size or not with a smaller or larger problem, the time should change in some reasonable way. If not, then you'd worry about it optimizing away, or clock speed warm-up effects (Idiomatic way of performance evaluation? for that and more, like page-faults.)

1. Why are there non-conditional jumps in code (at 403ad3, 403b53, 403d78 and 403d8f)?

Once you're already in an if block, you unconditionally know the else block should not run, so you jmp over it instead of jcc (even if FLAGS were still set so you didn't have to test the condition again). Or you put one or the other block out-of-line (like at the end of the function, or before the entry point) and jcc to it, then it jmps back to after the other side. That allows the fast path to be contiguous with no taken branches.

1. Why are there 3 retq instances in the same function with only one return path (at 403c0a, 403ca4 and 403d26)?

Duplicate ret comes from "tail duplication" optimization, where multiple paths of execution that all return can just get their own ret instead of jumping to a ret. (And copies of any cleanup necessary, like restoring regs and stack pointer.)

So your temp := value when ... else ... statement only works outside of a process statement. So you've got three options.

Upgrade to VHDL 2008, where you can also use this kind of statement in a process.

Use a global variable to store the next value... something like:

So apparently there are 4 following questions in your post:

• Question 1: So in summary, all those methods can be used in async fifo right?

• Question 2: And the set_false_path is the most simple way. No need to worry about the mcp cycle or max delay. I guess we use it only when the logic between 2 FF is "combinational"? Can we use it when there are sequence logic between 2 cross domain FF?

• Question 3: If ignoring all timing calculations using FP is bad, when is it a good time to use it? In theory I can replace all the FP with MCP.

• Question 4: What factors do you need to consider in order to choose the most suitable constraints?

Following are the 4 answers to aforementioned questions:

Answer 1: As shown below in figure, with an asynchronous FIFO, data can arrive at arbitrary time intervals on the transmission side, and the receiving side pulls data out of the queue as it has the bandwidth to process it.

Therefore, Yes, you can use all those optimizations/constraints/methods for asynchronous FIFO.

Answer 2: Yes set_false_path can be considered as one of the most simplest. And as the following figure shows, you are right we use when the logic between 2 FF is "combinational"?

Furthermore, based on my understanding, we do not use for sequence logic.

Answer 3: A false path is similar to the multicycle path in that it is not required to propagate signals within a single clock period. The difference is that a false path is not logically possible as dictated by the design. In other words, even though the timing analysis tool sees a physical path from one point to the other through a series of logic gates, it is not logically possible for a signal to propagate between those two points during normal operation. The main difference between a multicycle path with many available cycles (large n) versus a false path is that the multicycle path will still be checked against setup and hold requirements and will still be included in the timing analysis. It is possible for a multicycle path to still fail timing, but a false path will never have any associated timing violations.

Hence use a multicycle path in place of a false path constraint when:

• your intent is only to relax the timing requirements on a synchronous path; but
• the path still must be timed, verified and optimized.

Answer 4: Although a very valid question yet too broad. It all depends on the underlying design. Most implementation tools for FPGA layout have a plenty of optimization options. And obviously not all constraints are used by all steps in the compilation flow. Based on my experience and citing from Reference 1 the constraints that must be included in every design include all clock definitions, I/O delays, pin placements, and any relaxed constraints including multicycle and false paths.

Following two main references can further explain you to understand the the use of constraints:

• Reference 1
• Reference 2

As I mentioned, I highly suggest you take a look at the Kotlin Koans since they walk you through many examples that I think would certainly teach you how to perform almost all of those TODO's! (and they have the solutions!)

In this interview were testing whether you knew on how to use the aggregate and mapping functions from the Kotlin Standard Library and checking whether you would see that there was a lot of code that you could re-use by making them functions with the right amount of parameters

Here's how I would approach it:

Split does not really work here but you can do something like this instead using a regular expression to capture multiple matches in your string input:

Since the code has two nested for-loops, each one proportional to n, a quadratic runtime can be expected.

The issue is that you have special characters in your column name, which need to be escaped in Altair (see e.g. the field documentation in https://altair-viz.github.io/user_guide/generated/core/altair.Color.html?highlight=escape)

Why is this? Characters like . and [] in Vega-Lite are used to access nested attributes of columns.

The easiest approach would be to avoid such special characters in your dataframe column names. Alternatively, you can escape the special characters with a back-slash (\) though be careful about the effect of back-slashes in Python strings (use an r prefix for raw string encoding). For example:

Reduce your code to this form:

Modifying the binding from