-- Eric Wheeler On Wed, 28 Jun 2017, Coly Li wrote: > On 2017/6/27 下午8:04, tang.junhui@xxxxxxxxxx wrote: > > Hello Eric, Coly, > > > > I use a 1400G SSD device a bcache cache device, > > and attach with 10 back-end devices, > > and run random small write IOs, > > when gc works, It takes about 15 seconds, > > and the up layer application IOs was suspended at this time, > > How could we bear such a long time IO stopping? > > Is there any way we can avoid this problem? > > > > I am very anxious about this question, any comment would be valuable. > > I encounter same situation too. > Hmm, I assume there are some locking issue here, to prevent application > to send request and insert keys in LSM tree, no matter in writeback or > writethrough mode. This is a lazy and fast response, I need to check the > code then provide an accurate reply :-) Should it bypass the cache during GC if GC takes longer than X amount of time? That might still need to wait if writing to invalidate since the btree needs updated to invalidate, so that may not be an option... -Eric
