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Re: [Xen-devel] [PATCH 0/7] oxenstored: improve transaction conflict handling



On Thu, Mar 17, 2016 at 05:51:08PM +0000, Jonathan Davies wrote:
> This patch series makes a substantial improvement to oxenstored's transaction
> handling.
> 
> The original design of oxenstored assumed that a transaction would only ever
> span a small subtree. In practice this is rarely the case and means that other
> xenstore traffic overlapping with a transaction can cause it to fail with
> EAGAIN. This leads to significant performance problems with toolstack 
> operations
> when there is a certain level of xenstore traffic coming from other sources.
> 
> Instead, we observe that, although the transaction may span a large subtree, 
> it
> is very unlikely to read or write the same keys as other xenstore traffic. 
> This
> observation leads to an improved transaction conflict-handling algorithm in
> which the transaction is replayed to check it is serializable. This approach 
> is
> superior in performance.
> 
> The sixth patch is the main one that changes the way transaction conflicts are
> handled. The first five patches prepare the way by performing some refactoring
> and addition of infrastructure that allows for transactions to be replayed. 
> The
> seventh patch adds some extra logging.

All the patches have quite the Reviewed-by list already so I would think
these can go in now?

Thought oddly I didn't see any discussion on xen-devel for this?

> 
> Jonathan Davies (7):
>   oxenstored: refactor putting response on wire
>   oxenstored: remove some unused parameters
>   oxenstored: refactor request processing
>   oxenstored: keep track of each transaction's operations
>   oxenstored: move functions that process simple operations
>   oxenstored: replay transaction upon conflict
>   oxenstored: log request and response during transaction replay
> 
>  tools/ocaml/xenstored/Makefile        |    1 +
>  tools/ocaml/xenstored/connection.ml   |    5 +-
>  tools/ocaml/xenstored/define.ml       |    1 +
>  tools/ocaml/xenstored/oxenstored.conf |    1 +
>  tools/ocaml/xenstored/process.ml      |  344 
> +++++++++++++++++++++------------
>  tools/ocaml/xenstored/transaction.ml  |   21 +-
>  tools/ocaml/xenstored/xenstored.ml    |    1 +
>  7 files changed, 239 insertions(+), 135 deletions(-)
> 
> -- 
> 1.7.10.4
> 
> 
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