Re: [9fans] Async clunk?

[Bruce Ellis <bruce.ellis@gmail.com>]

trust me - experiment. ask questions. i'll send code. it can be an
enormous speedup.

brucee

On Mon, Aug 9, 2010 at 12:17 AM, Venkatesh Srinivas <me@acm.jhu.edu> wrote:
> On Sun, Aug 8, 2010 at 3:10 AM, Charles Forsyth <forsyth@terzarima.net>
> wrote:
>>
>> >Perhaps we could turn on async clunk for other files when the chan has
>> >CCACHE set (mount -C iirc). We already believe that the fileserver is
>> >'decent' then...
>>
>> that's more plausible, since you've declared that you're not interested
>> in certain details, but then the larger question arises: why pick on
>> clunk?
>> in Op, the thing that reduces network latency is combining the sequence
>> open, (read|write), close
>> into a single operation.
>
> When we tried out async Clunk in the Journal Callbacks work, it offered some
> fairly great improvements; and the details that it varies in are very minor
> compared to uncached 9p, particularly for decent fileservers.
> Since Clunk cannot fail, this also admits a simple (perhaps) approximation -
> issue the clunk as expected, but do not wait for RClunk.
>> services that wait for a close to commit,
> Hmm. Does this mean that any modification to devmnt, to keep a larger pool
> of FDs active for example, rather than clunking eagerly while walking, is
> unsafe? That would hold around directory FDs, which would make services like
> the above unhappy, or at least behave differently. Perhaps those file
> servers are assuming something not specified in the 9p definitions?
> Also, cyclic structures in Limbo with file descriptors embedded will not
> release the FD immediately after the outer structure is discarded. In a
> sense, that is also a delayed Clunk...
> -- vs
>
>