From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f182.google.com (mail-pd0-f182.google.com [209.85.192.182]) by dpdk.org (Postfix) with ESMTP id 34D6D7E28 for ; Tue, 16 Dec 2014 17:46:52 +0100 (CET) Received: by mail-pd0-f182.google.com with SMTP id p10so14143834pdj.41 for ; Tue, 16 Dec 2014 08:46:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=bR39hthdFeVRV8kdXsqiCIVGeV+EWa8q/7Ed5Zt+aCM=; b=oCKLYm/8ZObVzy6fUTZrnKy62NFp5bLFG5xor8ZrUNZX0W5hQyzYrtMi9GtQfmXuJ0 myiYtbPIa3/oDmQlAroZel7XPdxfgkMmzkX2KcLfcT5p451+2Q3rnlbpZzZ9qYd1CElN RGlOA9nh/zMp0HaCIynJYylIG1toNqtGzogfMdsH3t8CxC/p9JguAEwqbODpREMdzuW1 OZ2CPmKewDcw6zmonnBXTbX4+EY10faOmGEOayeS5HTH6LxjA2pdbryvBVSyHKEzIBVQ gq4+XC8poSRGBp3rrpEGesqSJ3X1CRlL9pzav93GIn2cTwadD/l7gmSoBpB/uGZa9lti uhJQ== MIME-Version: 1.0 X-Received: by 10.68.189.167 with SMTP id gj7mr6474718pbc.58.1418748411122; Tue, 16 Dec 2014 08:46:51 -0800 (PST) Received: by 10.70.136.201 with HTTP; Tue, 16 Dec 2014 08:46:51 -0800 (PST) In-Reply-To: <20141213103921.GA1162@localhost.localdomain> References: <20141213103921.GA1162@localhost.localdomain> Date: Tue, 16 Dec 2014 08:46:51 -0800 Message-ID: From: Ravi Kerur To: Neil Horman Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.15 Cc: "dev@dpdk.org" Subject: Re: [dpdk-dev] [PATCH] Minor fixes in rte_common.h file. 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, 16 Dec 2014 16:46:52 -0000 On Sat, Dec 13, 2014 at 2:39 AM, Neil Horman wrote: > > On Fri, Dec 12, 2014 at 03:04:34PM -0800, r k wrote: > > Subject: [PATCH] Minor fixes in rte_common.h file. > > > > Fix rte_is_power_of_2 since 0 is not. > > Avoid branching instructions in RTE_MAX and RTE_MIN. > > > > Signed-off-by: Ravi Kerur > > --- > > lib/librte_eal/common/include/rte_common.h | 6 +++--- > > lib/librte_pmd_e1000/igb_pf.c | 4 ++-- > > lib/librte_pmd_ixgbe/ixgbe_pf.c | 4 ++-- > > 3 files changed, 7 insertions(+), 7 deletions(-) > > > > diff --git a/lib/librte_eal/common/include/rte_common.h > > b/lib/librte_eal/common/include/rte_common.h > > index 921b91f..e163f35 100644 > > --- a/lib/librte_eal/common/include/rte_common.h > > +++ b/lib/librte_eal/common/include/rte_common.h > > @@ -203,7 +203,7 @@ extern int RTE_BUILD_BUG_ON_detected_error; static > > inline int rte_is_power_of_2(uint32_t n) { > > - return ((n-1) & n) == 0; > > + return n && !(n & (n - 1)); > > } > > > > /** > > @@ -259,7 +259,7 @@ rte_align64pow2(uint64_t v) #define RTE_MIN(a, b) > ({ \ > > typeof (a) _a = (a); \ > > typeof (b) _b = (b); \ > > - _a < _b ? _a : _b; \ > > + _b ^ ((_a ^ _b) & -(_a < _b)); \ > Are you sure this is actually faster than the branch version? What about > using > a cmov instead? > > i am pretty sure modified code is faster than branching. I remember cmov had performance issues esp. on Pentuim-4 not sure how new intel cpu's perform. > }) > > > > /** > > @@ -268,7 +268,7 @@ rte_align64pow2(uint64_t v) #define RTE_MAX(a, b) > ({ \ > > typeof (a) _a = (a); \ > > typeof (b) _b = (b); \ > > - _a > _b ? _a : _b; \ > > + _a ^ ((_a ^ _b) & -(_a < _b)); \ > Same as above > > Same as above. > > }) > > > > /*********** Other general functions / macros ********/ diff --git > > a/lib/librte_pmd_e1000/igb_pf.c b/lib/librte_pmd_e1000/igb_pf.c index > > bc3816a..546499c 100644 > > --- a/lib/librte_pmd_e1000/igb_pf.c > > +++ b/lib/librte_pmd_e1000/igb_pf.c > > @@ -321,11 +321,11 @@ igb_vf_set_mac_addr(struct rte_eth_dev *dev, > uint32_t > > vf, uint32_t *msgbuf) static int igb_vf_set_multicast(struct > rte_eth_dev > > *dev, __rte_unused uint32_t vf, uint32_t *msgbuf) { > > - int i; > > + int16_t i; > > uint32_t vector_bit; > > uint32_t vector_reg; > > uint32_t mta_reg; > > - int entries = (msgbuf[0] & E1000_VT_MSGINFO_MASK) >> > > + int32_t entries = (msgbuf[0] & E1000_VT_MSGINFO_MASK) >> > > E1000_VT_MSGINFO_SHIFT; > NAK, this has nothing to do with the included changelog > It does, it causes compilation errors such as /root/dpdk-new/dpdk/lib/librte_pmd_e1000/igb_pf.c: In function \u2018igb_pf_mbx_process\u2019: /root/dpdk-new/dpdk/lib/librte_pmd_e1000/igb_pf.c:350:23: error: array subscript is above array bounds [-Werror=array-bounds] vfinfo->vf_mc_hashes[i] = hash_list[i]; ^ cc1: all warnings being treated as errors Also it is always better to use explicit int definitions esp. for 64bit systems. > > > uint16_t *hash_list = (uint16_t *)&msgbuf[1]; > > struct e1000_hw *hw = > > E1000_DEV_PRIVATE_TO_HW(dev->data->dev_private); > > diff --git a/lib/librte_pmd_ixgbe/ixgbe_pf.c > > b/lib/librte_pmd_ixgbe/ixgbe_pf.c index 51da1fd..426caf9 100644 > > --- a/lib/librte_pmd_ixgbe/ixgbe_pf.c > > +++ b/lib/librte_pmd_ixgbe/ixgbe_pf.c > > @@ -390,7 +390,7 @@ ixgbe_vf_set_multicast(struct rte_eth_dev *dev, > > __rte_unused uint32_t vf, uint32 > > struct ixgbe_hw *hw = > > IXGBE_DEV_PRIVATE_TO_HW(dev->data->dev_private); > > struct ixgbe_vf_info *vfinfo = > > *(IXGBE_DEV_PRIVATE_TO_P_VFDATA(dev->data->dev_private)); > > - int nb_entries = (msgbuf[0] & IXGBE_VT_MSGINFO_MASK) >> > > + int32_t nb_entries = (msgbuf[0] & IXGBE_VT_MSGINFO_MASK) >> > > IXGBE_VT_MSGINFO_SHIFT; > ditto > > uint16_t *hash_list = (uint16_t *)&msgbuf[1]; > > uint32_t mta_idx; > > @@ -399,7 +399,7 @@ ixgbe_vf_set_multicast(struct rte_eth_dev *dev, > > __rte_unused uint32_t vf, uint32 > > const uint32_t IXGBE_MTA_BIT_SHIFT = 5; > > const uint32_t IXGBE_MTA_BIT_MASK = (0x1 << IXGBE_MTA_BIT_SHIFT) > - > > 1; > > uint32_t reg_val; > > - int i; > > + int16_t i; > ditto > > Same as above. > > > > /* only so many hash values supported */ > > nb_entries = RTE_MIN(nb_entries, IXGBE_MAX_VF_MC_ENTRIES); > > -- > > 1.9.1 > > >