From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Van Haaren, Harry" Subject: Re: [PATCH] eal: added new `rte_lcore_is_service_lcore` API. Date: Mon, 28 Aug 2017 15:24:06 +0000 Message-ID: References: <1503501027-11046-1-git-send-email-pbhagavatula@caviumnetworks.com> <20170828113302.GA22141@PBHAGAVATULA-LT> <20170828150946.GA18980@PBHAGAVATULA-LT> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Cc: "dev@dpdk.org" To: Pavan Nikhilesh Bhagavatula Return-path: Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 09C2E11D4 for ; Mon, 28 Aug 2017 17:24:10 +0200 (CEST) In-Reply-To: <20170828150946.GA18980@PBHAGAVATULA-LT> Content-Language: en-US List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" > -----Original Message----- > From: Pavan Nikhilesh Bhagavatula [mailto:pbhagavatula@caviumnetworks.com= ] > Sent: Monday, August 28, 2017 4:10 PM > To: Van Haaren, Harry > Cc: dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH] eal: added new `rte_lcore_is_service_lcor= e` API. >=20 > On Mon, Aug 28, 2017 at 01:49:37PM +0000, Van Haaren, Harry wrote: > > > From: Pavan Nikhilesh Bhagavatula [mailto:pbhagavatula@caviumnetworks= .com] > > > Sent: Monday, August 28, 2017 12:33 PM > > > To: Van Haaren, Harry > > > Cc: dev@dpdk.org > > > Subject: Re: [dpdk-dev] [PATCH] eal: added new `rte_lcore_is_service_= lcore` API. > > > > > > On Mon, Aug 28, 2017 at 10:59:51AM +0000, Van Haaren, Harry wrote: > > > > > From: Pavan Nikhilesh [mailto:pbhagavatula@caviumnetworks.com] > > > > > Sent: Wednesday, August 23, 2017 4:10 PM > > > > > To: dev@dpdk.org > > > > > Cc: Van Haaren, Harry ; Pavan Nikhile= sh > > > > > > > > > > Subject: [dpdk-dev] [PATCH] eal: added new `rte_lcore_is_service_= lcore` API. > > > > > > > > > > This API can be used to test if an lcore(EAL thread) is a service= lcore. > > > > > > > > > > Signed-off-by: Pavan Nikhilesh > > > > > --- > > > > > lib/librte_eal/common/include/rte_lcore.h | 18 +++++++++++++++++= + > > > > > 1 file changed, 18 insertions(+) > > > > > > > > > > diff --git a/lib/librte_eal/common/include/rte_lcore.h > > > > > b/lib/librte_eal/common/include/rte_lcore.h > > > > > index 50e0d0f..7854ea1 100644 > > > > > --- a/lib/librte_eal/common/include/rte_lcore.h > > > > > +++ b/lib/librte_eal/common/include/rte_lcore.h > > > > > @@ -180,6 +180,24 @@ rte_lcore_is_enabled(unsigned lcore_id) > > > > > } > > > > > > > > > > /** > > > > > + * Test if an lcore is service lcore. > > > > > + * > > > > > + * @param lcore_id > > > > > + * The identifier of the lcore, which MUST be between 0 and > > > > > + * RTE_MAX_LCORE-1. > > > > > + * @return > > > > > + * True if the given lcore is service; false otherwise. > > > > > + */ > > > > > +static inline int > > > > > +rte_lcore_is_service_lcore(unsigned lcore_id) > > > > > +{ > > > > > + struct rte_config *cfg =3D rte_eal_get_configuration(); > > > > > + if (lcore_id >=3D RTE_MAX_LCORE) > > > > > + return 0; > > > > > + return cfg->lcore_role[lcore_id] =3D=3D ROLE_SERVICE; > > > > > +} > > > > > > > > No header file and Static inline - so this is only to be used inter= nally in the service > > > cores library? > > > > If so, the function should actually be used, instead of only added = but not used in the > > > library itself. > > > > > > > > > > The enum rte_lcore_role_t has ROLE_SERVICE which tells that a particu= lar lcore is > > > a service lcore as well as an EAL thread some libraries such as rte_t= imer allow > > > specific operations only over EAL threads. > > > > Understood that role of cores is important, and that rte_timer might re= quire this > information. > > > > > > > The rte_timer lib uses the rte_is_lcore_enabled() call to check if a = lcore is an > > > EAL thread, Which checks if the lcore role is ROLE_RTE. But it shoul= d also > > > allow timers to be registered on a service core as processing those t= imers can > > > be done on them. > > > > No problem from me here either - although it's the Timers library maint= ainer that should > check this. > > > > > > > This new function allows such libraries to check if the role is > > > ROLE_SERVICE and allow those operations. > > > > If the timers library requires information about service-cores, it shou= ld use a public API > to retrieve that information. Having "internal" functions between librari= es is not nice. > > > > I think a better design would be to add this function as a public funct= ion, (add it to the > .map files etc) and then call the public function from the timers library= . > > > > Does that sound like a good solution? -Harry > > >=20 > The file rte_lcore.h is in librte_eal/common/include I couldn't find a .m= ap > file for eal/common and also other functions that are present in rte_lcor= e.h > aren't mapped in eal/linuxapp or eal/bsdapp. > I think it is fine as the functions are static inline. >=20 > -Pavan OK - I was looking at this from a service core library POV. The intent seem= s to be to update EAL in order to allow detection of a core having a ROLE_S= ERVICE. Now I see your intent better, no problem with the approach. Correct= that static-inline functions don't need .map file entries (cause they're i= nlined :) One technical issue: > + if (lcore_id >=3D RTE_MAX_LCORE) > + return 0; This should return a -ERROR value, as 0 is a valid return value that should= indicate one thing (and one thing only) "not a service core". Please spin a v2 and I'll Ack. >=20 > > > > > Currently, the only rte_timer library has this specific role check. T= he > > > following patch shows the usage in rte_timer library. > > > > > > http://dpdk.org/dev/patchwork/patch/27819/ > > > > > > > Or am I mis-understanding the intent? > > > > > > > > -Harry > > > > > > Thanks, > > > Pavan.