On 12/21/19 11:45 AM, Benjamin Mahler wrote: > + Jens > > Sounds like some of the iouring findings are surprising to Jens (the > author). > > Is there a benchmark he can run to look into this? > > Do you have more explanation about "silently ignore parts of the > requested events on an undocumented subset of file description types"?
Switch to private email, it's more convenient. I just sent this one to Marc separately, FWIW: Someone pointed me at this: https://www.mail-archive.com/[email protected]/msg02767.html And while I'm glad to see some io_uring adoption, I'm a bit puzzled at some of this. First of all, I downloaded the release and looked at your 'general notes' about io_uring. Comments on some of them: e) what kernel are you using? 5.3 (iirc) and newer supports two mmaps for this, mapping the two rings in one call. the sqes are separate, so can't really be folded with this. g) but you have timeout commands, if you want to get woken. h+i) 32k is max today, and since 5.5 we handle overflows much more gracefully. io_uring never drops events anymore. j) where are the details on this? you mention this in the release as well, but this is the first I've heard of this. aio and io_uring use the same mechanism for this, so not surprising that they share whatever quirk this is. doesn't mean it can't get fixed up though, but hard to fix something up if nobody told me about it. For the posting, I'd love to be able to benchmark this. How do you benchmark against libev using different backends? And back to e), what kernel did you use? We're obviously maturing this API (and adding features) as we go, and while most bugs fixes do make it back to -stable, that's not always true. I'd love to know more about oopses you've seen, and on what kernel you ran. -- Jens Axboe -- Jens Axboe _______________________________________________ libev mailing list [email protected] http://lists.schmorp.de/mailman/listinfo/libev
