On Thu, 1 Sep 2022 21:35:32 -0400 Kent Overstreet <kent.overstreet@xxxxxxxxx> wrote: > On Thu, Sep 01, 2022 at 08:23:11PM -0400, Steven Rostedt wrote: > > If ftrace, perf, bpf can't do what you want, take a harder look to see if > > you can modify them to do so. > > Maybe we can use this exchange to make both of our tools better. I like your > histograms - the quantiles algorithm I've had for years is janky, I've been > meaning to rip that out, I'd love to take a look at your code for that. And > having an on/off switch is a good idea, I'll try to add that at some point. > Maybe you got some ideas from my stuff too. > > I'd love to get better tracepoints for measuring latency - what I added to > init_wait() and finish_wait() was really only a starting point. Figuring out > the right places to measure is where I'd like to be investing my time in this > area, and there's no reason we couldn't both be making use of that. Yes, this is exactly what I'm talking about. I'm not against your work, I just want you to work more with everyone to come up with ideas that can help everyone as a whole. That's how "open source communities" is suppose to work ;-) The histogram and synthetic events can use some more clean ups. There's a lot of places that can be improved in that code. But I feel the ideas behind that code is sound. It's just getting the implementation to be a bit more efficient. > > e.g. with kernel waitqueues, I looked at hooking prepare_to_wait() first but not > all code uses that, init_wait() got me better coverage. But I've already seen > that that misses things, too, there's more work to be done. I picked prepare_to_wait() just because I was hacking up something quick and thought that was "close enough" ;-) -- Steve
