On Fri, Sep 16, 2016 at 02:01:00PM +0000, Cata Vasile wrote: > Hi, > > We've tried to test and benchmark your submitted work[1]. > > Cryptographic offloading is also used in IPsec in the Linux Kernel. In > heavy traffic scenarios, the NIC driver competes with the crypto device > driver. Most NICs use the NAPI context, which is one of the most > prioritized context types. In IPsec scenarios the performance is > trashed because, although raw data gets in to device, the data is > encrypted/decrypted and the dequeue code in CAAM driver has a hard time > being scheduled to actually call the callback to notify the networking > stack it can continue working with that data. Having received a reply from Thomas Gleixner today, there appears to be some disagreement with your findings, and a suggestion that the problem needs proper and more in-depth investigation. Thomas indicates that the NAPI processing shows an improvement when moved to the same context that threaded interrupts run in, as opposed to the current softirq context - which also would run the tasklets. What I would say is that if threaded IRQs are causing harm, then there seems to be something very wrong somewhere. > Being this scenario, at heavy load, the Kernel warns on rcu stalls and > the forwarding path has a lot of latency. Have you tried benchmarking > the board you used for testing? It's way too long ago for me to remember - these patches were created almost a year ago - October 20th 2015, which is when I'd have tested them. So, I'm afraid I can't help very much at this point, apart from trying to re-run some benchmarks. I'd suggest testing the openssl (with AF_ALG support), which is probably what I tested and benchmarked. However, as I say, it's far too long ago for me to really remember at this point. > I have ran some on our other platforms. The after benchmark fails to > run at the top level of the before results. Sorry, that last sentence doesn't make any sense to me. I don't have the bandwidth to look at this, and IPsec doesn't interest me one bit - I've never been able to work out how to setup IPsec locally. From what I remember when I looked into it many years ago, you had to have significant information about ipsec to get it up and running. Maybe things have changed since then, I don't know. If you want me to reproduce it, please send me a step-by-step idiots guide on setting up a working test scenario which reproduces your problem. Thanks. -- RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net. -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
