如何在乘客的所有正在运行的红宝石线程上获得堆栈跟踪

I have a production ruby sinatra app running on nginx/passenger, and I frequently see requests get inexplicably stalled. I wrote a script to call passenger-status on my cluster of machines every ten seconds and plot the results on a graph. This is what I see:I have a production ruby sinatra app running on