On Wed, 2021-07-21 at 20:34 -0700, Bart Van Assche wrote: > Using the UTRLCNR register involves two MMIO accesses in the hot path > while > > using the doorbell register only involves a single MMIO access. Since > MMIO > > accesses take time, do not use the UTRLCNR register. The spinlock > contention > > on the SCSI host lock that is reintroduced by this patch will be > addressed > > by a later patch. > > > > This reverts commit 6f7151729647e58ac7c522081255fd0c07b38105. Bart, This commit is the key change in "Optimize host lock on TR send/compl paths and utilize UTRLCNR" https://patchwork.kernel.org/project/linux-scsi/cover/1621845419-14194-1-git-send-email-cang@xxxxxxxxxxxxxx/. How did you compare the performance gain/loss after reverting this commit? Kind regards, Bean
