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. 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? I have ran some on our other platforms. The after benchmark fails to run at the top level of the before results. The rcu stall does not always stall in the same place. The after ping latency is greater, and oscillates a lot. It might be a good idea for the codebase to change to a threadirq, but from a pragmatic perspective, the whole system has to suffer. That is one the reasons most crypto accelerators try to run dequeue primitives in high priority contexts. Regards, Catalin Vasile [1] https://git.kernel.org/cgit/linux/kernel/git/herbert/cryptodev-2.6.git/commit/?id=66d2e2028091a074aa1290d2eeda5ddb1a6c329c -- 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
