在 2024/9/4 1:28, Bart Van Assche 写道: > [外部邮件] > 此邮件来源于小米公司外部，请谨慎处理。若对邮件安全性存疑，请将邮件转发给misec@xxxxxxxxxx进行反馈 > > > On 9/3/24 4:54 AM, ZhangHui wrote: >> Currently, for a controller that supports multiple queues, like UFS4.0, >> the mq_ops->complete is executed in the interrupt top-half. Therefore, >> the file system's end io is executed during the request completion >> process, >> such as f2fs_write_end_io on smartphone. >> >> However, we found that the execution time of the file system end io >> is strongly related to the size of the bio and the processing speed >> of the CPU. Because the file system's end io will traverse every page >> in bio, this is a very time-consuming operation. >> >> We measured that the 80M bio write operation on the little CPU will >> cause the execution time of the top-half to be greater than 100ms. >> The CPU tick on a smartphone is only 4ms, which will undoubtedly affect >> scheduling efficiency. >> >> Let's fixed this issue by moved non sync request completion flow to >> softirq, and keep the sync request completion in the top-half. > > An explanation is missing from the patch description why this issue > cannot be solved by changing rq_affinity to 2. > > Thanks, > > Bart. > hi Bart, Does set rq_affinity to 2 mean QUEUE_FLAG_SAME_COMP? This seems to determine on which core the current request is completed, rather than in the interrupt top or bottom half? Thanks Zhang
