Hi,
> -----Original Message-----
> From: dev <dev-boun...@dpdk.org> On Behalf Of Pavan Nikhilesh
> Bhagavatula
> Sent: Tuesday, April 23, 2019 17:13
> To: tho...@monjalon.net
> Cc: dev@dpdk.org; jer...@marvell.com; Marko Kovacevic
> <marko.kovace...@intel.com>; Ori Kam <or...@mellanox.com>; Bruce
> Richardson <bruce.richard...@intel.com>; Pablo de Lara
> <pablo.de.lara.gua...@intel.com>; Radu Nicolau <radu.nico...@intel.com>;
> akhil.go...@nxp.com; Tomasz Kantecki <tomasz.kante...@intel.com>;
> sta...@dpdk.org
> Subject: Re: [dpdk-dev] [PATCH] examples/l3fwd: fix em mode datapath
> selection
>
>
>
> >-----Original Message-----
> >From: dev <dev-boun...@dpdk.org> On Behalf Of Thomas Monjalon
> >Sent: Tuesday, April 23, 2019 2:05 PM
> >To: Pavan Nikhilesh Bhagavatula <pbhagavat...@marvell.com>
> >Cc: dev@dpdk.org; Jerin Jacob Kollanukkaran <jer...@marvell.com>; Marko
> >Kovacevic <marko.kovace...@intel.com>; Ori Kam <or...@mellanox.com>;
> >Bruce Richardson <bruce.richard...@intel.com>; Pablo de Lara
> ><pablo.de.lara.gua...@intel.com>; Radu Nicolau
> ><radu.nico...@intel.com>; Akhil Goyal <akhil.go...@nxp.com>; Tomasz
> >Kantecki <tomasz.kante...@intel.com>; sta...@dpdk.org
> >Subject: Re: [dpdk-dev] [PATCH] examples/l3fwd: fix em mode datapath
> >selection
> >
> >23/04/2019 04:47, Pavan Nikhilesh Bhagavatula:
> >>From: Thomas Monjalon <tho...@monjalon.net>
> >> >10/04/2019 09:29, Pavan Nikhilesh Bhagavatula:
> >> >> From: Pavan Nikhilesh <pbhagavat...@marvell.com>
> >> >>
> >> >> Currently, l3wfd em mode has two datapath modes em_sequential
> and
> >> >> em_hlm. We can select either of them by defining
> >> >NO_HASH_MULTI_LOOKUP
> >> >> to one or zero.
> >> >> The code checks if NO_HASH_MULTI_LOOKUP is defined or not
> instead
> >> >> of checking for the value.
> >> >>
> >> >> Fixes: 52c97adc1f0f ("examples/l3fwd: fix exact match
> >> >> performance")
> >> >> Cc: sta...@dpdk.org
> >> >>
> >> >> Signed-off-by: Pavan Nikhilesh <pbhagavat...@marvell.com>
> >> >> ---
> >> >> --- a/examples/l3fwd/l3fwd_em.c
> >> >> +++ b/examples/l3fwd/l3fwd_em.c
> >> >> #if defined RTE_ARCH_X86 || defined
> RTE_MACHINE_CPUFLAG_NEON
> >-#if
> >> >> defined(NO_HASH_MULTI_LOOKUP)
> >> >> +#if NO_HASH_MULTI_LOOKUP
> >> >
> >> >A quick grep shows that it used in another place with #ifdef:
> >> >
> >> >examples/l3fwd/l3fwd.h:#if !defined(NO_HASH_MULTI_LOOKUP) &&
> >> >defined(RTE_MACHINE_CPUFLAG_NEON)
> >> >
> >> >
> >>
> >> #if !defined(NO_HASH_MULTI_LOOKUP) &&
> >> defined(RTE_MACHINE_CPUFLAG_NEON) #define
> >NO_HASH_MULTI_LOOKUP 1
> >> #endif
> >>
> >> This macro is used to set l3fwd_em_sequential as the default EM
> >> datapath on AARCH64 as its performance is better.
> >> (http://patches.dpdk.org/patch/49372/)
> >>
> >> make -C examples/l3fwd #Selects l3fwd_em_sequential by default
> on
> >AARCH 64
> >>
> >> Currently, we cannot select em_hlm without manually editing the macro
> >> as using the below command still sets em_sequential as the default
> >> datapath because the macro modified in the patch that selects the
> >> datapath
> >checks if NO_HASH_MULTI_LOOKUP is defined or not rather than its value.
> >>
> >> EXTRA_CFLAGS='-DNO_HASH_MULTI_LOOKUP=0' make -C
> examples/l3fwd
> >>
> >> I hope I cleared up things a bit.
> >
> >In my understanding, we should check the value in the other case too,
> >instead of #if defined.
>
> That will lead to undefined and redefined error:
>
> [dpdk] # make -C examples/l3fwd
> make: Entering directory '/root/pavan/dpdk-int/examples/l3fwd'
> CC main.o
> CC l3fwd_lpm.o
> In file included from /root/dpdk/examples/l3fwd/l3fwd_lpm.c:28:0:
> /root/dpdk/examples/l3fwd/l3fwd.h:14:6: error:
> "NO_HASH_MULTI_LOOKUP" is not defined, evaluates to 0 [-Werror=undef]
> #if !NO_HASH_MULTI_LOOKUP &&
> defined(RTE_MACHINE_CPUFLAG_NEON)
>
> [dpdk] # EXTRA_CFLAGS='-DNO_HASH_MULTI_LOOKUP=0' make -C
> examples/l3fwd
> make: Entering directory '/root/dpdk/examples/l3fwd'
> CC main.o
> ]
> #define NO_HASH_MULTI_LOOKUP 1
> n file included from /root/dpdk/examples/l3fwd/l3fwd_lpm.c:28:0:
> <command-line>:0:0: note:
>
> ] #define
> NO_HASH_MULTI_LOOKUP 1is the location of the previous definition
>
> >
> >
Actually I looked at this EM lookup mode selection issue as well, and my first
solution is the same as yours :)
I didn't find out a way to enable selection without using compile options
(-DNO_HASH_MULTI_LOOKUP etc.).
Maybe we can use both HASH_MULTI_LOOKUP and NO_HASH_MULTI_LOOKUP like below:
--- a/examples/l3fwd/l3fwd.h
+++ b/examples/l3fwd/l3fwd.h
@@ -11,8 +11,8 @@
#define RTE_LOGTYPE_L3FWD RTE_LOGTYPE_USER1
-#if !defined(NO_HASH_MULTI_LOOKUP) && defined(RTE_MACHINE_CPUFLAG_NEON)
-#define NO_HASH_MULTI_LOOKUP 1
+#if !defined(HASH_MULTI_LOOKUP) && defined(RTE_MACHINE_CPUFLAG_NEON)
+#define NO_HASH_MULTI_LOOKUP
#endif
Not sure if this is a good idea.
PS: if we are controlling selection using compile options, it is better to be
documented somewhere.
