Return-Path: X-Original-To: apmail-hadoop-user-archive@minotaur.apache.org Delivered-To: apmail-hadoop-user-archive@minotaur.apache.org Received: from mail.apache.org (hermes.apache.org [140.211.11.3]) by minotaur.apache.org (Postfix) with SMTP id 04DBB9F6C for ; Thu, 11 Oct 2012 17:57:07 +0000 (UTC) Received: (qmail 17806 invoked by uid 500); 11 Oct 2012 17:57:02 -0000 Delivered-To: apmail-hadoop-user-archive@hadoop.apache.org Received: (qmail 17689 invoked by uid 500); 11 Oct 2012 17:57:02 -0000 Mailing-List: contact user-help@hadoop.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@hadoop.apache.org Delivered-To: mailing list user@hadoop.apache.org Received: (qmail 17681 invoked by uid 99); 11 Oct 2012 17:57:02 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 11 Oct 2012 17:57:02 +0000 X-ASF-Spam-Status: No, hits=-0.7 required=5.0 tests=RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of russell.jurney@gmail.com designates 209.85.216.176 as permitted sender) Received: from [209.85.216.176] (HELO mail-qc0-f176.google.com) (209.85.216.176) by apache.org (qpsmtpd/0.29) with ESMTP; Thu, 11 Oct 2012 17:56:56 +0000 Received: by mail-qc0-f176.google.com with SMTP id n41so1896828qco.35 for ; Thu, 11 Oct 2012 10:56:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=references:from:in-reply-to:mime-version:date:message-id:subject:to :content-type:content-transfer-encoding; bh=mYYlJYg56fAVo3xpEDf0UroTvmDbWnaCA93h9SmBff4=; b=YYPC9rE5jgVnDmciG13abxqHZM0ZFrY0SVVwmqaM2O3HebtFnyC17FIZoL7K9NV6PS 7iwhtD6BUhebAvo34VU56nk8pEtOSR7p2jgf2PXVcC+hm1Nf7YswhLvvcbgOqGX7VPD7 lOg8sTerAGZCb+QGHAW0TCpI+vjcaZYDtxlzMUSFE4+LkxTlJvYlnV/ue88DIXHknZhc teVzSo5t8kjZMBFnLTPq/gX5U1yfxwK6wYpmHnc9toh/Z2s37IJEXDQVYkV7NYSMOViz k0K4w99U6eHZhae41RCiCUl0qDv9A3Rn385Hz27LXusqDDPDF9X7NHtHTX6g5BD3g0vp PkpQ== Received: by 10.49.63.97 with SMTP id f1mr3807052qes.4.1349978195689; Thu, 11 Oct 2012 10:56:35 -0700 (PDT) References: From: Russell Jurney In-Reply-To: Mime-Version: 1.0 (1.0) Date: Thu, 11 Oct 2012 10:56:36 -0700 Message-ID: <4215577957656723663@unknownmsgid> Subject: Re: Why they recommend this (CPU) ? To: "user@hadoop.apache.org" Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Virus-Checked: Checked by ClamAV on apache.org Anyone got data on this? This is interesting, and somewhat counter-intuitiv= e. Russell Jurney http://datasyndrome.com On Oct 11, 2012, at 10:47 AM, Jay Vyas wrote: > Presumably, if you have a reasonable number of cores - speeding the cores= up will be better than forking a task into smaller and smaller chunks - be= cause at some point the overhead of multiple processes would be a bottlenec= k - maybe due to streaming reads and writes? I'm sure each and every probl= em has a different sweet spot.