Re: [dpdk-dev] [PATCH v4 0/3] timer library enhancement

[Thomas Monjalon <thomas@monjalon.net>]

This patchset is waiting for review.

Robert, are you available?

19/09/2017 19:02, Erik Gabriel Carrillo:
> In the current implementation of the DPDK timer library, timers can be
> created and set to be handled by a target lcore by adding it to a
> skiplist that corresponds to that lcore.  However, if an application
> enables multiple lcores, and each of these lcores repeatedly attempts
> to install timers on the same target lcore, overall application
> throughput will be reduced as all lcores contend to acquire the lock
> guarding the single skiplist of pending timers. 
> 
> This patchset addresses this scenario by adding an option to enable an
> array of skiplists in each lcore's priv_timer struct. Then, when lcore i
> installs a timer on lcore k, the timer will be added to the ith skiplist
> for lcore k.  If lcore j installs a timer on lcore k simultaneously,
> lcores i and j can both proceed since they will be acquiring different
> locks for different lists. This functionality is off by default, and
> can be enabled via a new function.
> 
> When lcore k processes its pending timers, if the multiple pending list
> option is enabled, it will traverse skiplists in its array and acquire 
> the current skiplist's lock while a run list is broken out; meanwhile,
> all other lists can continue to be modified.  Then, all run lists for
> lcore k are collected and traversed together so timers are executed in
> their relative order. If the multiple pending list option is not enabled
> (the default), only a single list will be traversed, as before.
> 
> Erik Gabriel Carrillo (3):
>   timer: add multiple pending lists option for each lcore
>   timer: handle timers installed from non-EAL threads
>   doc: update timer lib docs