RE: [EXT] Re: [PATCH v4 21/22] pdcp: add thread safe processing

[Anoob Joseph <anoobj@marvell.com>]

Hi Stephen,

I've dropped this patch for now. Based on what we conclude on this thread, will post this as a separate patch as required.

Thanks,
Anoob

> -----Original Message-----
> From: Anoob Joseph <anoobj@marvell.com>
> Sent: Saturday, May 27, 2023 10:55 AM
> To: Stephen Hemminger <stephen@networkplumber.org>
> Cc: Thomas Monjalon <thomas@monjalon.net>; Akhil Goyal
> <gakhil@marvell.com>; Jerin Jacob Kollanukkaran <jerinj@marvell.com>;
> Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>; Volodymyr Fialko
> <vfialko@marvell.com>; Hemant Agrawal <hemant.agrawal@nxp.com>;
> Mattias Rönnblom <mattias.ronnblom@ericsson.com>; Kiran Kumar
> Kokkilagadda <kirankumark@marvell.com>; dev@dpdk.org; Olivier Matz
> <olivier.matz@6wind.com>
> Subject: RE: [EXT] Re: [PATCH v4 21/22] pdcp: add thread safe processing
> 
> Hi Stephen,
> 
> Please see inline.
> 
> Thanks,
> Anoob
> 
> > -----Original Message-----
> > From: Stephen Hemminger <stephen@networkplumber.org>
> > Sent: Saturday, May 27, 2023 3:42 AM
> > To: Anoob Joseph <anoobj@marvell.com>
> > Cc: Thomas Monjalon <thomas@monjalon.net>; Akhil Goyal
> > <gakhil@marvell.com>; Jerin Jacob Kollanukkaran <jerinj@marvell.com>;
> > Konstantin Ananyev <konstantin.v.ananyev@yandex.ru>; Volodymyr
> Fialko
> > <vfialko@marvell.com>; Hemant Agrawal <hemant.agrawal@nxp.com>;
> > Mattias Rönnblom <mattias.ronnblom@ericsson.com>; Kiran Kumar
> > Kokkilagadda <kirankumark@marvell.com>; dev@dpdk.org; Olivier Matz
> > <olivier.matz@6wind.com>
> > Subject: [EXT] Re: [PATCH v4 21/22] pdcp: add thread safe processing
> >
> > External Email
> >
> > ----------------------------------------------------------------------
> > On Sat, 27 May 2023 02:32:13 +0530
> > Anoob Joseph <anoobj@marvell.com> wrote:
> >
> > > +static inline uint32_t
> > > +pdcp_atomic_inc(uint32_t *val, const bool mt_safe) {
> > > +	if (mt_safe)
> > > +		return __atomic_fetch_add(val, 1, __ATOMIC_RELAXED);
> > > +	else
> > > +		return (*val)++;
> > > +}
> >
> > This is a bad pattern. None of the rest of DPDK does this.
> > Either be thread safe or not.
> 
> [Anoob] Most protocol implementation would have a similar issue. I've tried
> to follow the approach taken in lib IPsec (please check lib/ipsec/ipsec_sqn.h).
> From the discussion we had on v3, I've tried to make it compile time constant
> to remove any conditional checks in datapath.
> 
> If you still think, this is an issue, I could drop this patch for now and re-
> introduce it later once we have test applications that can work with traffic.
> Please share your thoughts.