[SCM] Samba Shared Repository - branch v3-2-test updated - initial-v3-2-test-2626-g719527f

Volker Lendecke Volker.Lendecke at SerNet.DE
Fri Feb 29 18:30:58 GMT 2008

On Fri, Feb 29, 2008 at 10:57:03AM -0500, David Collier-Brown wrote:
>  In tests with both ufs and qfs many moons ago, we found that
> the speed *leaped* up for large files and large read sizes: 
> gifs attached.
> >We could pass io_bufsize to cli_pull, but then I would
> >really like to increase the default value of io_bufsize to
> >at least half a meg.
> Big buffers only *start* helping at 64 KB.  Large is good,
> and it's especially good if the read size is bigger than the 
> file (;-)) 
> The reason they help independent of the network speed
> is that large reads and writes trigger both read ahead
> add I/O coalescing, which work together to produce
> and M * M kind of an improvement.

The async code should eliminate the network round trips, so
the server-side pread calls should fly in as quickly as the
CPU allows. Are you saying that small sequential reads will
never trigger any kernel-level readahead?

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