Updated patch attached. It does seem to help - just tried an experiment

      dd if=/mnt/test/1GBfile of=/dev/null bs=1M count=1024

to the same server, same share and compared mounting with rasize=6MB
vs. default (1MB to Azure)

(rw,relatime,vers=3.1.1,cache=strict,username=linuxsmb3testsharesmc,uid=0,noforceuid,gid=0,noforcegid,addr=20.150.70.104,file_mode=0777,dir_mode=0777,soft,persistenthandles,nounix,serverino,mapposix,mfsymlinks,nostrictsync,rsize=1048576,wsize=1048576,bsize=1048576,echo_interval=60,actimeo=1,multichannel,max_channels=2)

Got 391 MB/s  with rasize=6MB, much faster than default (which ends up
as 1MB with current code) of 163MB/s






# dd if=/mnt/test/394.29520 of=/dev/null bs=1M count=1024 ; dd
if=/mnt/scratch/394.29520 of=/mnt/test/junk1 bs=1M count=1024 ;dd
if=/mnt/test/394.29520 of=/dev/null bs=1M count=1024 ; dd
if=/mnt/scratch/394.29520 of=/mnt/test/junk1 bs=1M count=1024 ;
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 4.06764 s, 264 MB/s
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 12.5912 s, 85.3 MB/s
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 3.0573 s, 351 MB/s
1024+0 records in
1024+0 records out
1073741824 bytes (1.1 GB, 1.0 GiB) copied, 8.58283 s, 125 MB/s

On Sat, Apr 24, 2021 at 9:36 PM Steve French <smfrench@gmail.com> wrote:
>
> Yep - good catch.  It is missing part of my patch :(
>
> Ugh
>
> Will need to rerun and get real numbers
>
> On Sat, Apr 24, 2021 at 9:10 PM Matthew Wilcox <willy@infradead.org> wrote:
> >
> > On Sat, Apr 24, 2021 at 02:27:11PM -0500, Steve French wrote:
> > > Using the buildbot test systems, this resulted in an average improvement
> > > of 14% to the Windows server test target for the first 12 tests I
> > > tried (no multichannel)
> > > changing to 12MB rasize (read ahead size).   Similarly increasing the
> > > rasize to 12MB to Azure (this time with multichannel, 4 channels)
> > > improved performance 37%
> > >
> > > Note that Ceph had already introduced a mount parameter "rasize" to
> > > allow controlling this.  Add mount parameter "rasize" to cifs.ko to
> > > allow control of read ahead (rasize defaults to 4MB which is typically
> > > what it used to default to to the many servers whose rsize was that).
> >
> > I think something was missing from this patch -- I see you parse it and
> > set it in the mount context, but I don't see where it then gets used to
> > actually affect readahead.
>
>
>
> --
> Thanks,
>
> Steve



-- 
Thanks,

Steve