From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr0-f172.google.com (mail-wr0-f172.google.com [209.85.128.172]) by dpdk.org (Postfix) with ESMTP id 8B522D0A5 for ; Thu, 30 Mar 2017 17:12:58 +0200 (CEST) Received: by mail-wr0-f172.google.com with SMTP id w11so63711170wrc.3 for ; Thu, 30 Mar 2017 08:12:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=6wind-com.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=rFAG4mN2dwzYDFcU6D/yAm/qelSRhMM1jKtH5Nzklng=; b=HCbDfusX8dN+p59/cgRzxwUJe8COJFwCEKrhCyRB+4B4a/Rp8fVlzJGOS5Qqry2hFY mM+m6Ws5IAoSksZsjgcs2nIykjletS2aOATUN1sAh3jWqk9F+3aBT6ttd0VU47t8Isec TZtsVOB9l02f4j0IcalUiKkJgI+yU9u9OgVJXCw74IjBIHVantsKxNjC7bysSKOSlcqS xmiBDWUPRL1VtpIoJ10H/mYGk+h4M/HJ5AYOFAdZELeTYtCg0//sbMEpgyB/iEUrm2IY 2kVKIQnS9wlBs9QxiKlkMwhpHVFmdmFkq4C3dsEe/KMw+iVUhd5Dcsnx2LgOv0zIVufT qxNQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=rFAG4mN2dwzYDFcU6D/yAm/qelSRhMM1jKtH5Nzklng=; b=Riy3pKNplzu/6NDjfqBQ7qeveuK7mwpW7/n33FbP1Ph3Y5MbPMBUZdPHZS7tMt71+A 9viKypTlOEOjGwi/44/g8wfdIJ4ILSX28PA40tIbY+xuXpUe9ztHkgUe4FVFX/KGQxD3 PdKOMjQKoZfKFOgx8ELsy5BjzXEedyhEttiTqTdGGqmVgUpxwIbZkKMphgJjG/g0CCMJ tmSxWfkAYP4mgNbk9y3BFgwujOwj8xh8C6bko6xqxTpDljHDcQMDUw26h+hXxxQ3F6fm AAT0fWvGagVPU8xVMD41bR8m5AeFOm4R8+ipRq2IYaS71goT43TFhhQ9o1PDiHyUgcnV cxPg== X-Gm-Message-State: AFeK/H0ylHp33HILZRjTHWbCwWnxpZ0YqEK9PuBxGf8wJiaFLbqNlTQrkxIk7VmW7IBTkC+u X-Received: by 10.223.179.78 with SMTP id k14mr204159wrd.93.1490886778069; Thu, 30 Mar 2017 08:12:58 -0700 (PDT) Received: from platinum (2a01cb0c03c651000226b0fffeed02fc.ipv6.abo.wanadoo.fr. [2a01:cb0c:3c6:5100:226:b0ff:feed:2fc]) by smtp.gmail.com with ESMTPSA id w12sm3150274wra.21.2017.03.30.08.12.57 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Thu, 30 Mar 2017 08:12:57 -0700 (PDT) Date: Thu, 30 Mar 2017 17:12:54 +0200 From: Olivier Matz To: "Eads, Gage" Cc: "dev@dpdk.org" Message-ID: <20170330171254.3ad8ff1e@platinum> In-Reply-To: <9184057F7FC11744A2107296B6B8EB1E01E97BAD@FMSMSX108.amr.corp.intel.com> References: <1490202268-3799-1-git-send-email-gage.eads@intel.com> <1490278858-27257-1-git-send-email-gage.eads@intel.com> <20170324150444.233b3045@platinum> <9184057F7FC11744A2107296B6B8EB1E01E97BAD@FMSMSX108.amr.corp.intel.com> X-Mailer: Claws Mail 3.14.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: [dpdk-dev] [PATCH v3] mempool: remove non-EAL thread note from header X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Mar 2017 15:12:58 -0000 Hi Gage, On Wed, 29 Mar 2017 15:30:49 +0000, "Eads, Gage" wrote: > > -----Original Message----- > > From: Olivier Matz [mailto:olivier.matz@6wind.com] > > Sent: Friday, March 24, 2017 9:05 AM > > To: Eads, Gage > > Cc: dev@dpdk.org > > Subject: Re: [PATCH v3] mempool: remove non-EAL thread note from header > > > > Hi Gage, > > > > On Thu, 23 Mar 2017 09:20:58 -0500, Gage Eads > > wrote: > > > Commit 30e6399892276 ("mempool: support non-EAL thread") added the > > > capability for non-EAL threads to use the mempool library. This commit > > > removes the note indicating that the mempool library cannot be used > > > safely by non-EAL threads. > > > > > > Also, fix a typo. > > > > > > Signed-off-by: Gage Eads > > > --- > > > v2: Changed commit message to referenced commit 30e63998 instead of > > > 4b5062755 > > > v3: Fix checkpatch error > > > > > > lib/librte_mempool/rte_mempool.h | 6 +----- > > > 1 file changed, 1 insertion(+), 5 deletions(-) > > > > > > diff --git a/lib/librte_mempool/rte_mempool.h > > > b/lib/librte_mempool/rte_mempool.h > > > index 991feaa..b1186fd 100644 > > > --- a/lib/librte_mempool/rte_mempool.h > > > +++ b/lib/librte_mempool/rte_mempool.h > > > @@ -53,11 +53,7 @@ > > > * > > > * Note: the mempool implementation is not preemptable. A lcore must > > > * not be interrupted by another task that uses the same mempool > > > - * (because it uses a ring which is not preemptable). Also, mempool > > > - * functions must not be used outside the DPDK environment: for > > > - * example, in linuxapp environment, a thread that is not created by > > > - * the EAL must not use mempools. This is due to the per-lcore cache > > > - * that won't work as rte_lcore_id() will not return a correct value. > > > + * (because it uses a ring which is not preemptible). > > > */ > > > > > > #include > > > > I agree the comment is not correct today. But I think we should still highlight > > that usual functions [ex: rte_mempool_get(), rte_mempool_put()] won't work > > when called on a non-EAL thread. > > My understanding is that non-EAL threads can call those functions, but their performance will suffer since they go directly to the underlying ring. Is that correct? Yes, that's more correct than what I wrote :) > > > > > Maybe it could be reworded in that way: > > > > """ > > Note: the mempool implementation is not preemptable. A lcore must not be > > interrupted by another task that uses the same mempool (because it uses a ring > > which is not preemptible). Also, usual mempool functions like > > rte_mempool_get() or rte_mempool_put() are designed to be called from an > > EAL thread due to the internal per-lcore cache. When using a mempool from a > > non-EAL thread, a user cache has to be provided to > > rte_mempool_generic_get() or rte_mempool_generic_put(). > > """ > > > > What do you think? > > Agreed, this looks better. If indeed non-EAL threads can call rte_mempool_get() and _put(), perhaps the last sentence can be reworked like so? > > Due to the lack of caching, rte_mempool_get() or rte_mempool_put() performance > will suffer when called by non-EAL threads. Instead, non-EAL threads should call > rte_mempool_generic_get() or rte_mempool_generic_put() with a user cache > created with rte_mempool_cache_create(). Looks good, thanks! Olivier > > > > > Thanks, > > Olivier