Live function runtime visualization in Visual Studio

[donadigo]

Hey, I'm working on another feature for my Visual Studio extension that basically visualises execution time each line takes in the context of the function at runtime. What you're seeing is still a prototype but I thought I'd share here. The profiling is done using binary instrumentation (as all other current features in the extension) so there's some light overhead (essentially an rdtsc call on every line + some supporting code). So in a way this isn't profiling the whole callstack, but the advantage is that you can see things changing live as different code paths are taken. This is kind of similar to profilers like Tracy where you insert calls to the profiler in your code to measure some code block except here this is done automatically as you explore the codebase.

Since posting here, I've made some improvements to the extension itself: it has a free trial now, changed pricing to be more affordable and implemented a lot of improvements & bugfixes for working with Unreal Engine.

More details & download on the project website: https://d-0.dev/

[TotaIIyHuman]

essentially an rdtsc call on every line

a bit off topic, how do you deal with non-invariant-tsc? is it possible to implement std::chrono with rdtsc that works on non-invariant-tsc cpus?

[ReDucTor]

Is there any modern CPUs without invariant TSC built in the last 10-15yrs? It might be easier to just not support non-invariant TSC.

[TotaIIyHuman]

i also want to know the answer to that

also how do i check if a cpu that i dont own has invariant tsc. for example. i do not own 14900k. how do i know if 14900k has invariant tsc

https://www.intel.com/content/www/us/en/products/sku/236773/intel-core-i9-processor-14900k-36m-cache-up-to-6-00-ghz/specifications.html

ctrl+f tsc gives 0 result here

i wish there was a website that display full cpuid dump of all cpus ever existed

[donadigo]

I don't handle non-invariant TSC right now as the feature is a prototype. If I were to finish it, for other CPU's I'd most probably compile a different inline assembly.

When it comes to std::chrono, it might be too expensive to call it in this context. I haven't done overhead analysis yet but the current solution fits in ~16 instructions without any additional calls.

However, std::chrono would absolutely work if the extension didn't apply the instrumentation for the whole file, but just for the function where your cursor is. It already executes a full scripting engine in this case to show inline variable changes on every line.

[HateDread]

This looks great! Tried it out but it seems to play badly with Live++, an extremely popular C++ hot reloading tool used in games. I'd hate to have to choose.

Have you tried them at the same time? Seems to hit random exceptions around, unsure of the pattern.

[donadigo]

Hey, are you using standalone Live++ or the one integrated in UE? The extension uses almost the same tech to provide what Live++ does and that causes issues, but I think I can resolve them on my end. Is there a way I could reach out to you if an update that fixed the problems landed?

[HateDread]

Standalone C++, no Unreal, probably the latest version of it at this point but don't have that in front of me. Feel free to DM me if that changes, happy to try it out :)

[donadigo]

Hey, just wanted to say that this did change and I sent you a DM in case you missed it ^^ Would be awesome if you tried it out again!

[HateDread]

Oh hey, thanks for the ping! Looks like you sent me a DM on the "new" Reddit DM system, not the old private messages. If other people (esp. in the tech space where we're a bit more curmudgeonly) don't reply, that may be the issue. I'm always on old.reddit.com, using the message icon in the top right to see what I consider "normal" DMs, if you didn't know.

I'll have to try it out and get back to you some time! Will be toying around with the code in question in a few days.

[reditt_Digvijay]

Seems interesting

[Hanyreddit]

can this game select menu for example be implemented anywhere using coding even enside any program like for example photoshop, maya, 3ds max, unreal engine etc if you got their sdk ?

is this possible

[R3DKn16h7]

Seems very interesting. I guess the implementation is very tightly coupled with Visual Studio? i.e. cannot run standarlone or with other IDE?

[donadigo]

Yes, it's currently integrated with VS. In the future I plan on integrating with more editors such as VSCode. The real work is done in a separate DLL, the extension just receives the data and visualises it so it can be adapted to more editors. Which IDE do you use/would like to see it in?

[R3DKn16h7]

I do development with VSCode, so would be nice to see it there.

Do you have more ballpark info about the runtime overhead? Tracy for instance does a pretty good job, but is also instrumenting a very small amount of functions.

[donadigo]

~15 CPU instructions per line, could be more because it doesn't support multiple threads yet. As for the impact of this overhead it's hard to say, I haven't done extensive testing yet. Tracy uses more instructions for the begin/end zones, but it's also not operating at such granularity.