Re: [dpdk-users] DPDK hash table dynamic growth

[Shyam Shrivastav <shrivastav.shyam@gmail.com>]

For theory on growing/shrinking hash tables useful MIT class

https://www.youtube.com/watch?v=BRO7mVIFt08

On Tue, Apr 18, 2017 at 1:36 AM, Alex Kiselev <kiselev99@gmail.com> wrote:

> If you need only a single reader and a single writer solution you can use
> any existing hash table implementation and build on top of it your own
> resizable version. You can try a straightforward approach. Create a new
> bigger hash table when the old is full and just copy key/values into it. A
> new reader/lookup function should take into account that during resizing
> there can be more then one hash table and check all of them. And I wouldn't
> copy all keys at once, but instead I'd copy N keys at one iteration of the
> lcore main loop so the resizing process don't block other operations.
>
> пн, 17 апр. 2017 г. в 20:44, Fu, Qiaobin <qiaobinf@bu.edu>:
>
> > Thanks @Alex and @Stephen for pointing these valuable materials to me!
> >
> > Maybe it’s better that I can clarify my scenarios more. Actually, we are
> > using RSS (source + destination IP) to distribute packets, so we are
> > maintaining one hash table per lcore (thread), and there is no need for
> > synchronization issue in our case. If there are more solutions, please
> let
> > me know. I will compare the solutions, and pick up the best suitable one.
> >
> > Best,
> > Qiaobin
> >
> > On Apr 17, 2017, at 1:30 PM, Alex Kiselev <kiselev99@gmail.com> wrote:
> >
> > I would take a look at:
> >
> > 1) http://preshing.com/20160201/new-concurrent-hash-maps-for-cpp/
> > 2) https://github.com/efficient/libcuckoo
> > 3)
> >
> > http://high-scale-lib.cvs.sourceforge.net/viewvc/high-
> scale-lib/high-scale-lib/org/cliffc/high_scale_lib/
> NonBlockingHashMap.java?view=markup
> > https://www.youtube.com/watch?v=HJ-719EGIts
> > https://www.youtube.com/watch?v=WYXgtXWejRM
> >
> > But there is a catch, none of them is written in C.
> >
> > 2017-04-17 19:54 GMT+03:00 Stephen Hemminger <stephen@networkplumber.org
> >:
> >
> > On Mon, 17 Apr 2017 15:47:59 +0000
> > "Fu, Qiaobin" <qiaobinf@bu.edu> wrote:
> >
> > Hello,
> >
> > Currently, I am using the hash library to handle network flows defined as
> > source and destination IP addresses. I need to find a way to alleviate
> > memory pressure when the table is full. However, after some research, I
> > didn’t find any hints on the dynamic growth in the hash library. Could
> > anyone point me some hints on this? Thanks.
> >
> > Best,
> > Qiaobin
> >
> >
> > If you need growing hash table, I recommend the lock-free hash table in
> > the Linux userspace RCU library;
> > rather than the more limited DPDK one.
> >
> >
> >
> >
> > --
> > --
> > Kiselev Alexander
> >
> >
> > --
> --
> Kiselev Alexander
>