Question(s) about smbd in respect to preadv2

Volker Lendecke Volker.Lendecke at SerNet.DE
Sun Jan 25 03:23:04 MST 2015

On Sat, Jan 24, 2015 at 03:39:03PM -0800, Jeremy Allison wrote:
> Because it allows a client to have multiple outstanding
> read and write IOops to a single smbd daemon.
> This is important if a client has multiple processes
> reading and writing multiple large files - the client
> redirector just pipelines to the number of outstanding
> SMB2 credits.
> Using pthreadpool then allows a single smbd to have
> multiple preads/pwrites outstanding.

Another important point for preadv2 is server-side CPU
utilization. Samba has a lot of OEMs that use very
low-powered CPUs like MIPS and ARM that can not afford the
additional thread switch cycle budget. As pointed out in my
other mail, the preadv2 good case will be the same as the
sync case CPU-wise, so it will be interesting to compare CPU
as well if you want to make the case for preadv2.


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