These graphs show the distribution of latencies for each terminal. If we measure the latency from keypress to internal screen capture on my laptop, we see the following latencies for different terminals
Let’s look at some different terminals to see if any terminals add enough latency that we’d expect the difference to be noticeable. Another thing I care about is latency, but knowing that a particular terminal has high stdout throughput tells me little to nothing about its latency. The speed at which I can scroll up or down an entire page sounds related, but in actual measurements the two are not highly correlated (e.g., emacs-eshell is quick at scrolling but extremely slow at sinking stdout). The closest thing that I care about is the speed at which I can ^C a command when I’ve accidentally output too much to stdout, but as we’ll see when we look at actual measurements, a terminal’s ability to absorb a lot of input to stdout is only weakly related to its responsiveness to ^C. I can’t recall the last task I did which was limited by the speed at which I can cat a file to stdout on my terminal (well, unless I’m using eshell in emacs), nor can I think of any task for which that sub-measurement is useful. This is pretty much as useless a benchmark as I can think of. Second, the most common terminal benchmark I see cited (by at least two orders of magnitude) is the rate at which a terminal can display output, often measured by running cat on a large file. First, I spend most of my time in a terminal and usually do editing in a terminal, so the latency I see is at least the latency of the terminal. Personally, I’d like to see the latency of different terminals and shells for a couple of reasons. How much time do non-game applications take? Pavel Fatin measured this for text editors and found latencies ranging from a few milliseconds to hundreds of milliseconds and he did this with an app he wrote that we can use to measure the latency of other applications that uses to generate keypresses and do screen captures. Menzel budgets 33ms to the game, half for game logic and half for rendering. While games often do much more work per frame than “typical” applications, they’re also much better optimized than “typical” applications. Keypress-to-display measurements are mostly done in games because gamers care more about latency than most people, but I don’t think that most applications are all that different from games in terms of latency. It’s possible to tune things to get into the 40ms range, but the vast majority of users don’t do that kind of tuning, and even if they do, that’s still quite far from the 10ms to 20ms range, where tablets and VR start to feel really “right”. Note that this assumes a gaming mouse and a pretty decent LCD it’s common to see substantially slower latency for the mouse and for pixel switching.
#Terminal emulator mac professional
The idea that computers respond quickly to input, so quickly that humans can’t notice the latency, is the most common performance-related fallacy I hear from professional programmers. People often tell me that’s true, but I think it’s just the opposite. One reason might be that keyboard and mouse input are quick and that inputs are reflected nearly instantaneously, but I don’t think that’s true. 20ms feels fine, 50ms feels laggy, and 150ms feels unbearable.Ĭuriously, I rarely hear complaints about keyboard and mouse input being slow. You can also see something similar if you try VR headsets with different latencies.
#Terminal emulator mac android
The Apple device has well above 10ms end-to-end latency, but the difference is still quite dramatic - it’s enough that I’ll actually use the new iPad Pro to take notes or draw diagrams, whereas I find Android tablets unbearable as a pen-and-paper replacement. the current generation iPad Pro with the Apple stylus. If you want to see a mini version of this for yourself, you can try a random Android tablet with a stylus vs. At 10ms (1/100th of a second), the latency is noticeable, but the experience is ok, and at < 1ms the experience is great, as good as pen and paper. At 100ms (1/10th of a second), which is typical of consumer tablets, the experience is terrible. If you don’t want to watch the three minute video, they basically created a device which could simulate arbitrary latencies down to a fraction of a millisecond.
There’s a great MSR demo from 2012 that shows the effect of latency on the experience of using a tablet.