> ufs_bsg was introduced nearly three years ago and it allocates its own > request queue. This is not related with ufs_bsg. I want to talk about a member under ufs_hba, cmd_queue. Very sorry for making you confused. > I faced a sytmpom with this and want to ask something about it. > > That is, sometimes queue depth for ufs is limited to half of the its > maximum value even in a situation with many IO requests from filesystem. > It turned out that it only occurs when a query is being processed at the > same time. > Regarding my tracing, when the query process starts, users for the hctx > that represents a ufs host increase to two and with this, some pathes > calling 'hctx_may_queue' > function in blk-mq seems to throttle dispatches, technically with 16 > because the number of ufs slots (32 in my case) is dividend by two (users). > > I found that it happened when a query for write booster is processed > because write booster only turns on in some conditions in my base that is > different from kernel mainline. But when an exceptional event or others > that could lead to a query occurs, it can happen even in mainline. > > I think the throttling is a little bit excessive, so the question: is > there any way to assign queue depth per user on an asymmetric basis? > > Thanks. > Kiwoong Kim
