Date: Fri, 6 Oct 2017 19:02:48 +0000 From: Rick Macklem <rmacklem@uoguelph.ca> To: "freebsd-current@freebsd.org" <freebsd-current@freebsd.org> Subject: RFC how to use kernel procs/threads efficiently Message-ID: <YQXPR0101MB099752292CCAC9E8A72C1E96DD710@YQXPR0101MB0997.CANPRD01.PROD.OUTLOOK.COM>
next in thread | raw e-mail | index | archive | help
Hi,
I have now dropped the client side of Flexible File Layout for pNFS into he=
ad
and I believe it is basically working.
Currently when talking to mirrored DS servers, it does the Write and Commit
RPCs to the mirrors serially. This works, but is inefficient w.r.t. elapsed=
to to
completion.
To do them concurrently, I need separate kernel processes/threads to do the=
m.
I can think of two ways to do this:
1 - The code that I have running in projects/pnfs-planb-server for the pNFS=
server
side does a kproc_create() to create a kernel process that does the R=
PC and
then krpc_exit()s.
- This was easy to code and works. However, I am concerned that there=
is
going to be excessive overheads from doing all the kproc_create()s =
and
kproc_exit()s?
Anyone know if these calls will result in large overheads?
2 - I haven't coded this, but the other way I can think of to do this is to
create a pool of threads (kthread_create() is sufficient in this case=
, I
think?) and then hand each RPC to an available thread so it can do th=
e RPC.
- Other than a little more complex coding, the main issue I see with =
this one
is "How many threads and when to create more/less of them.".
Anyhow, any comments w.r.t. the merits of either of the above approaches
(or a suggestion of other ways to do this) would be appreciated, rick=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?YQXPR0101MB099752292CCAC9E8A72C1E96DD710>