On Fri, 2022-02-11 at 23:52 -0800, Abhinav Kumar wrote: > > The thread is writing the data to a file in local storage. From our > profiling, the read is the one taking the time not the write. > That seems kind of hard to believe, let's say it's a 4/3 split (4 minutes reading, 3 minutes writing, to make read > write as you say), and 3MiB size, that'd mean you get 12.8KiB/sec? That seems implausibly low, unless you're reading with really tiny buffers? Can you strace this somehow? (with timestamp info) > Just doubling what we have currently. I am not sure how the current 5 > mins timeout came from. > To be honest it came out of thin air, and wasn't really meant as a limit on how fast you can read (feels like even if it's tens of MiB you should read it in milliseconds into userspace), but more of a maximum time that we're willing to waste kernel memory if nobody is around to read the data. I thought it'd be better if we could somehow pin it while the userspace is reading it, but OTOH maybe that's actually bad, since that means userspace (though suitably privileged) could pin this kernel memory indefinitely. johannes
