Re: kern/55268: tmpfs is slow

[Andrew Doran <ad%netbsd.org@localhost>]

The following reply was made to PR kern/55268; it has been noted by GNATS.

From: Andrew Doran <ad%netbsd.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: kern-bug-people%netbsd.org@localhost, gnats-admin%netbsd.org@localhost,
	netbsd-bugs%netbsd.org@localhost
Subject: Re: kern/55268: tmpfs is slow
Date: Fri, 15 May 2020 22:53:29 +0000

 It's a little better now but there is still a major problem with lock
 contention and context switch storms during fault processing because of a
 mix of reader/writer holds on the uobject locks.
 
 http://www.netbsd.org/~ad/2020/tmpfs-sucks.svg
 
 I guess it's something to do with tmpfs pages always being marked
 UVM_PAGE_STATUS_UNKNOWN unless committed to swap and that affecting the
 fault type.
 
 Andrew