5 ms·

What's the purpose of visualizing it as grid? I thought it might be good for debugging periodic events (e.g., every 16ms for rendering at 60fps) but it seems li

by zawerf 9y ago

What's the purpose of visualizing it as grid? I thought it might be good for debugging periodic events (e.g., every 16ms for rendering at 60fps) but it seems like this is fixed to one sec for one column. For example in the flame graph in chrome's performance tab, you can select/slice/zoom/pan arbitrary time ranges. If you want the high level view you just zoom out.

brendangregg 9y ago
Supporting different y-axis ranges is something we can add, and I was already thinking of adding a 1ms range for visualizing low-level CPU cycle activities (which span nano and microseconds). I like the idea of 16ms for 60fps analysis, where every column is one frame. Could help game development. :)
- saulrh 9y ago
  Actually, seeing the diagonal stripes in the examples [1], maybe it'd be useful to have a mode that lets you rescale the axes to line the stripes up? If you're using this to inspect patterns, it seems to me that the most useful time scale would not be a nice round human number, it'd be one that matches well with the patterns you're trying to inspect - one period, not one second. Way out in the distance, maybe even a variable-interval mode, where you can click-select blocks and each one is given its own column, so you can directly compare them without the dead space in the middle and starting from the same baseline? [1] Particularly striking: https://cdn-images-1.medium.com/max/2000/1*EypUnkPtayeKr9bJuvgNEg.png https://cdn-images-1.medium.com/max/2000/1*EypUnkPtayeKr9bJu...
  - Scaevolus 9y ago
    You could autoscale the y axis to whatever makes the columns have the most similarity (minimize squared differences).
    - simsla 9y ago
      Rather than lsq, you could use autocorrelation within rows to line them up.
      - rakoo 9y ago
        This thing is extremely periodic. You should do an FFT, there should be a peak that's more obvious than the others. That's your frequency and thus your period.
nsarafa 9y ago
I think it's helpful for visualizing the seconds as it's a time based focused debugger. Maybe open a pull request for a graph based view and we can A/B test ️
kbenson 9y ago
one second per column, fractions of a second per row, individual cells are fractions of that column's second. In your example, I imagine you might see a periodic color shift along the Y axis as things aligned with that 16ms window. The example grid looks to have about 50 rows, so that would be ~20ms each, which is a bit too large for your use case. The example usage shows that you get to define the Hertz is samples at though, so you should be able to define exactly the period length you desire.

by zawerf 9y ago

brendangregg 9y ago

Supporting different y-axis ranges is something we can add, and I was already thinking of adding a 1ms range for visualizing low-level CPU cycle activities (which span nano and microseconds). I like the idea of 16ms for 60fps analysis, where every column is one frame. Could help game development. :)

saulrh 9y ago
Actually, seeing the diagonal stripes in the examples [1], maybe it'd be useful to have a mode that lets you rescale the axes to line the stripes up? If you're using this to inspect patterns, it seems to me that the most useful time scale would not be a nice round human number, it'd be one that matches well with the patterns you're trying to inspect - one period, not one second. Way out in the distance, maybe even a variable-interval mode, where you can click-select blocks and each one is given its own column, so you can directly compare them without the dead space in the middle and starting from the same baseline? [1] Particularly striking: https://cdn-images-1.medium.com/max/2000/1*EypUnkPtayeKr9bJuvgNEg.png https://cdn-images-1.medium.com/max/2000/1*EypUnkPtayeKr9bJu...
- Scaevolus 9y ago
  You could autoscale the y axis to whatever makes the columns have the most similarity (minimize squared differences).
  - simsla 9y ago
    Rather than lsq, you could use autocorrelation within rows to line them up.
    - rakoo 9y ago
      This thing is extremely periodic. You should do an FFT, there should be a peak that's more obvious than the others. That's your frequency and thus your period.

nsarafa 9y ago

I think it's helpful for visualizing the seconds as it's a time based focused debugger. Maybe open a pull request for a graph based view and we can A/B test ️

kbenson 9y ago

one second per column, fractions of a second per row, individual cells are fractions of that column's second. In your example, I imagine you might see a periodic color shift along the Y axis as things aligned with that 16ms window. The example grid looks to have about 50 rows, so that would be ~20ms each, which is a bit too large for your use case. The example usage shows that you get to define the Hertz is samples at though, so you should be able to define exactly the period length you desire.