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. > > Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx> > Cc: Stanley Chu <stanley.chu@xxxxxxxxxxxx> > Cc: Can Guo <cang@xxxxxxxxxxxxxx> > Cc: Asutosh Das <asutoshd@xxxxxxxxxxxxxx> > Cc: Avri Altman <avri.altman@xxxxxxx> > Signed-off-by: Bart Van Assche <bvanassche@xxxxxxx> > Hi Bart, I did the comparison test on my platform, it is very difficult to get a very clear and fair result between two changes. but lamely speaking, on the small chunk size read/write, your changes wins. but on the big chunk size, It is not very clear, the gap between the two changes can be ignored. Tested-by: Bean Huo <beanhuo@xxxxxxxxxx> Bean
