On Mon, Dec 19, 2022 at 04:02:10PM -0600, Robert Elliott wrote: > This is an offshoot of the previous patch series at: > https://lore.kernel.org/linux-crypto/20221219202910.3063036-1-elliott@xxxxxxx > > Add a kernel_fpu_yield() function for x86 crypto drivers to call > periodically during long loops. > > Test results > ============ > I created 28 tcrypt modules so modprobe can run concurrent tests, > added 1 MiB functional and speed tests to tcrypt, and ran three processes > spawning 28 subprocesses (one per physical CPU core) each looping forever > through all the tcrypt test modes. This keeps the system quite busy, > generating RCU stalls and soft lockups during both generic and x86 > crypto function processing. > > In conjunction with these patch series: > * [PATCH 0/8] crypto: kernel-doc for assembly language > https://lore.kernel.org/linux-crypto/20221219185555.433233-1-elliott@xxxxxxx > * [PATCH 0/3] crypto/rcu: suppress unnecessary CPU stall warnings > https://lore.kernel.org/linux-crypto/20221219202910.3063036-1-elliott@xxxxxxx > * [PATCH 0/3] crypto: yield at end of operations > https://lore.kernel.org/linux-crypto/20221219203733.3063192-1-elliott@xxxxxxx > > while using the default RCU values (60 s stalls, 21 s expedited stalls), > several nights of testing did not result in any RCU stall warnings or soft > lockups in any of these preemption modes: > preempt=none > preempt=voluntary > preempt=full > > Setting the shortest possible RCU timeouts (3 s, 20 ms) did still result > in RCU stalls, but only about one every 2 hours, and not occurring > on particular modules like sha512_ssse3 and sm4-generic. > > systemd usually crashes and restarts when its journal becomes full from > all the tcrypt printk messages. Without the patches, that triggered more > RCU stall reports and soft lockups; with the patches, only userspace > seems perturbed. > Where does this patch series apply to? - Eric
