Day 7: Tackling Mic Gain Problems and Exploring High-Frequency Trading
Let’s be real: some days of development are 10% coding and 90% fighting your tools. Day 7 was exactly that—a mix of OBS audio tuning, "Day 1" algorithm logic, and deep-level C++ concurrency.
Check the live session here: Watch on YouTube
🎙️ The "Pre-Game" Struggle: Audio is Hard
Before hitting a single line of C++, I spent the first 10 minutes fighting OBS Studio. If your mic gain is too low, nobody listens. If it’s too high, you’re clipping and blowing out eardrums.
- The Fix: Added a Gain Filter in OBS, settling between 13 dB and 19 dB.
- Pro-tip: Use Noise Suppression (RNNoise) if you’re coding in a room with a loud fan or Indian street traffic.
🧠 Algorithmic Evolution: The Sliding Window
We tackled the Maximum Average Subarray problem. The naive way to find the average of elements in an array of size is . That's garbage.
The "Sliding Window" Optimization
Instead of re-summing elements every time, you just:
- Subtract the element leaving the window.
- Add the element entering the window.
Performance Hack: Don’t calculate the average inside the loop. Division is expensive for a CPU. Compare the sums instead, and do a single division at the very end.
// Optimized Logic
for (int i = k; i < nums.size(); ++i) {
currentSum += nums[i] - nums[i - k];
maxSum = std::max(maxSum, currentSum);
}
return (double)maxSum / k; // Single division = Win
🏎️ C++ Micro-Optimizations for HFT
When building a Trading Terminal (which I’ve renamed to Hir Trader to avoid trademark drama), every clock cycle is a liability.
1. Prefix vs. Postfix
Stop using i++. Use ++i.
i++(Postfix) creates a temporary copy of the object before incrementing.++i(Prefix) increments in place. In a loop running millions of times, those temporary objects add up to a performance tax you don't want to pay.
2. False Sharing & Cache Alignment
In multithreaded trading engines, two threads can fight over the same Cache Line even if they are touching different variables.
- The Solution: Use
alignas(64)to ensure your atomic variables stay on their own cache lines. This prevents "False Sharing," which can destroy your throughput faster than a bad algorithm.
📅 The Workflow: Discipline > Motivation
I’m keeping a strict work log and using WinGet for package management to keep the environment clean. Most of the heavy lifting is in C++ and CMake, with a focus on benchmarking the matching engine to handle 100+ orders with sub-millisecond latency.
Cultural Note
While the West worries about Friday the 13th, we’re out here celebrating Sankranti and Ekadashi. It's a good reminder that perspective changes everything—whether in life or in code.
What's Next?
The benchmark results for the matching engine are coming next. I’ll be pushing the concurrency-safe structures to GitHub soon.
#CPlusPlus #HFT #CodingLife #SoftwareEngineering #Optimization #SlidingWindow
