[tahoe-lafs-trac-stream] [Tahoe-LAFS] #3787: Is the use of Pipeline for write actually necessary?

[Tahoe-LAFS]

#3787: Is the use of Pipeline for write actually necessary?
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     Reporter:  itamarst  |      Owner:
         Type:  task      |     Status:  new
     Priority:  normal    |  Milestone:  HTTP Storage Protocol v2
    Component:  unknown   |    Version:  n/a
   Resolution:            |   Keywords:
Launchpad Bug:            |
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Changes (by itamarst):

 * milestone:  HTTP Storage Protocol => HTTP Storage Protocol v2


Old description:

> It was added in #392, but I really don't understand the reasoning.
>
> It makes a bit more sense if you replace the word "pipeline" with
> "batcher" when reading the code, but I still don't understand why round-
> trip-time is improved by this approach.

New description:

 Updated issue description: there is a single hardcoded value for batching
 (formerly known as pipelining) immutable uploads, and it might be better
 to be dynamic. Or higher, at least.


 ----

 Initial issue description:

 Pipeline class was added in #392, but I really don't understand the
 reasoning.

 It makes a bit more sense if you replace the word "pipeline" with
 "batcher" when reading the code, but I still don't understand why round-
 trip-time is improved by this approach.

--

Comment:

 Once #3939 is fixed, the Pipeline class will no longer be used. However,
 there will still be a batching mechanism via
 `allmydata.immutable.layout._WriteBuffer`, which suffers from basically
 the same issue of having a single hardcoded number that isn't necessarily
 adapted to network conditions.

 So this still should be thought about based on discussion above, but
 changing the summary and description.

--
Ticket URL: <https://tahoe-lafs.org/trac/tahoe-lafs/ticket/3787#comment:4>
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