From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by dpdk.org (Postfix) with ESMTP id 52F3FCE7 for ; Tue, 10 Feb 2015 07:57:27 +0100 (CET) Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga101.jf.intel.com with ESMTP; 09 Feb 2015 22:57:26 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,548,1418112000"; d="scan'208";a="664122920" Received: from pgsmsx103.gar.corp.intel.com ([10.221.44.82]) by fmsmga001.fm.intel.com with ESMTP; 09 Feb 2015 22:57:24 -0800 Received: from shsmsx104.ccr.corp.intel.com (10.239.4.70) by PGSMSX103.gar.corp.intel.com (10.221.44.82) with Microsoft SMTP Server (TLS) id 14.3.195.1; Tue, 10 Feb 2015 14:57:23 +0800 Received: from shsmsx102.ccr.corp.intel.com ([169.254.2.62]) by SHSMSX104.ccr.corp.intel.com ([169.254.5.161]) with mapi id 14.03.0195.001; Tue, 10 Feb 2015 14:57:23 +0800 From: "Liang, Cunming" To: Olivier MATZ , "dev@dpdk.org" Thread-Topic: [dpdk-dev] [PATCH v4 07/17] eal: add rte_gettid() to acquire unique system tid Thread-Index: AQHQPoxlK7byiujpnkC07bixNU4v85zmsJOAgALNhvA= Date: Tue, 10 Feb 2015 06:57:23 +0000 Message-ID: References: <1422491072-5114-1-git-send-email-cunming.liang@intel.com> <1422842559-13617-1-git-send-email-cunming.liang@intel.com> <1422842559-13617-8-git-send-email-cunming.liang@intel.com> <54D7C05F.9090501@6wind.com> In-Reply-To: <54D7C05F.9090501@6wind.com> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Subject: Re: [dpdk-dev] [PATCH v4 07/17] eal: add rte_gettid() to acquire unique system tid X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 10 Feb 2015 06:57:28 -0000 > -----Original Message----- > From: Olivier MATZ [mailto:olivier.matz@6wind.com] > Sent: Monday, February 09, 2015 4:01 AM > To: Liang, Cunming; dev@dpdk.org > Subject: Re: [dpdk-dev] [PATCH v4 07/17] eal: add rte_gettid() to acquire= unique > system tid >=20 > Hi, >=20 > On 02/02/2015 03:02 AM, Cunming Liang wrote: > > The rte_gettid() wraps the linux and freebsd syscall gettid(). > > It provides a persistent unique thread id for the calling thread. > > It will save the unique id in TLS on the first time. > > > > [...] > > > > +/** > > + * A wrap API for syscall gettid. > > + * > > + * @return > > + * On success, returns the thread ID of calling process. > > + * It always successful. > > + */ > > +int rte_sys_gettid(void); > > + > > +/** > > + * Get system unique thread id. > > + * > > + * @return > > + * On success, returns the thread ID of calling process. > > + * It always successful. > > + */ > > +static inline int rte_gettid(void) > > +{ > > + static RTE_DEFINE_PER_LCORE(int, _thread_id) =3D -1; > > + if (RTE_PER_LCORE(_thread_id) =3D=3D -1) > > + RTE_PER_LCORE(_thread_id) =3D rte_sys_gettid(); > > + return RTE_PER_LCORE(_thread_id); > > +} >=20 > Instead of doing the test each time rte_gettid() is called, why not > having 2 functions: > rte_init_tid() -> assign the per_lcore variable > rte_gettid() -> return the per_lcore variable [LCM] The rte_gettid() mainly used in recursive spinlock. For non-EAL thread, we don't expect new user thread has to explicit call so= mething. The purpose to call it in EAL thread init, is to lower down the overhead of= the first calling for EAL thread. >=20 >=20 >=20 > Regards, > Olivier