From: Jonathan L. <la...@us...> - 2001-09-12 19:56:27
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Alan Cox [al...@lx...] wrote: > > that Jonathon's small patch goes a long way towards resolving the most > > significant performance bottlenecks without a full subsystem rework, > > thereby dramatically reducing the risk of regression in a 2.4.X > > kernel. > > I am very concerned about the stability of such a change. What would be > useful data would be to know how much of the time that lock is held is by > the drivers not by the request queue code. Lock contention measurements using lockmeter indicate that block i/o subsystem function __make_request is the primary source of io_request_lock contention. (see http://marc.theaimsgroup.com/?l=lse-tech&m=100017134609802&w=2) My io_request_lock patch changes __make_request to use a per device queue lock (q->queue_lock) instead of io_request_lock without reducing the scope of other io_request_lock usage. Device drivers are not changed nor are they required to change by that patch. Please let me know if can address any other questions. Jonathan -- Jonathan Lahr IBM Linux Technology Center Beaverton, Oregon la...@us... 503-578-3385 |