Re: [dpdk-dev] [PATCH v4] mempool: remove memory wastage on non x86

[Thomas Monjalon <thomas@monjalon.net>]

20/01/2020 13:24, Olivier Matz:
> On Thu, Jan 16, 2020 at 06:40:23PM +0530, Jerin Jacob wrote:
> > On Wed, Jan 15, 2020 at 2:35 AM <jerinj@marvell.com> wrote:
> > >
> > > From: Jerin Jacob <jerinj@marvell.com>
> > >
> > > The existing optimize_object_size() function address the memory object
> > > alignment constraint on x86 for better performance.
> > >
> > > Different (micro) architecture may have different memory alignment
> > > constraint for better performance and it not the same as the existing
> > > optimize_object_size().
> > >
> > > Some use, XOR(kind of CRC) scheme to enable DRAM channel distribution
> > > based on the address and some may have a different formula.
> > >
> > > Introducing arch_mem_object_align() function to abstract
> > > the difference between different (micro) architectures to avoid
> > > wasting memory for mempool object alignment for the architecture
> > > that it is not required to do so.
> > >
> > > Details on the amount of memory saving:
> > >
> > > Currently, arm64 based architectures use the default (nchan=4,
> > > nrank=1). The worst case is for an object whose size (including mempool
> > > header) is 2 cache lines, where it is optimized to 3 cache lines (+50%).
> > >
> > > Examples for cache lines size = 64:
> > >   orig     optimized
> > >   64    -> 64           +0%
> > >   128   -> 192          +50%
> > >   192   -> 192          +0%
> > >   256   -> 320          +25%
> > >   320   -> 320          +0%
> > >   384   -> 448          +16%
> > >   ...
> > >   2304  -> 2368         +2.7%  (~mbuf size)
> > >
> > > Additional details:
> > > https://www.mail-archive.com/dev@dpdk.org/msg149157.html
> > >
> > > Signed-off-by: Jerin Jacob <jerinj@marvell.com>
> > > Reviewed-by: Gavin Hu <gavin.hu@arm.com>
> > 
> > Ping for merge.
> 
> Acked-by: Olivier Matz <olivier.matz@6wind.com>

Applied, thanks