From owner-freebsd-questions@FreeBSD.ORG Thu Sep 26 09:11:37 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 38D78E8D for ; Thu, 26 Sep 2013 09:11:37 +0000 (UTC) (envelope-from adrian.chadd@gmail.com) Received: from mail-wg0-x230.google.com (mail-wg0-x230.google.com [IPv6:2a00:1450:400c:c00::230]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id B6CCC2ADC for ; Thu, 26 Sep 2013 09:11:36 +0000 (UTC) Received: by mail-wg0-f48.google.com with SMTP id n12so832778wgh.15 for ; Thu, 26 Sep 2013 02:11:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=kto48lUlNvdJD5W1Qr9OCBx7nQN88ZxlG3pLBwsvKVo=; b=PzMZOfxqp8h1ZyN6l9R53LoczzBmtQqOe/UTZLo4rAbla2UdPMc7/Dg2BhntCXbFu5 vVloRRpuFfVWr1iTTkoKLgzVFx0PVDwYIS8gbcJMJEEH6967vKeSwWRWS5C+tQyjftT/ tHuhtbHRhq582heUhGmnPS1dES2MmQot2a2cBaHWzBnVBcZ+9SMLIG4z8Xl4i1RDjp6l pYZvff4ZBQZoong5r3+POp0Br0KP+DWanKvTk2me1bOfpDWz/DoJJxdyfNvznKTt6XHS oa1D9yEHx/+I+HhBNXwrahgG0hXpJqSM64I48M8nKKA+cY48uitaVGYY9LiSV4m2NSsx cKsA== MIME-Version: 1.0 X-Received: by 10.180.10.136 with SMTP id i8mr26512089wib.46.1380186695195; Thu, 26 Sep 2013 02:11:35 -0700 (PDT) Sender: adrian.chadd@gmail.com Received: by 10.216.73.133 with HTTP; Thu, 26 Sep 2013 02:11:35 -0700 (PDT) In-Reply-To: <20130922141034.d98d472e42c784062d66651c@yahoo.es> References: <52388C9B.6030205@foxbatcapital.com> <20130919155327.115e7344@sarvision.nl> <20130920110535.42c984da@sarvision.nl> <20130922141034.d98d472e42c784062d66651c@yahoo.es> Date: Thu, 26 Sep 2013 02:11:35 -0700 X-Google-Sender-Auth: p1KSZuvNtuet4zcsZqnrzH8rizw Message-ID: Subject: Re: this 48-core box... From: Adrian Chadd To: Eduardo Morras Content-Type: text/plain; charset=ISO-8859-1 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: FreeBSD Questions X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Sep 2013 09:11:37 -0000 The cache alignment happens because it hits a specific size threshold, and jemalloc/phkmalloc(I think!) just round everything up to be page size aligned. The underlying problem may actually be a code change to how the math is done. It just runs slower on page-aligned alignments.. adrian On 22 September 2013 05:10, Eduardo Morras wrote: > On Sat, 21 Sep 2013 12:53:36 -0700 > Adrian Chadd wrote: > > > .. just as a data point - there was a thread a while ago about numeric > > processing performance on linux vs bsd. > > > > It all boiled down to how jemalloc versus the linux allocator(s) allocate > > blocks. jemalloc will page align things after a certain size. Linux > didn't. > > So when doing numeric processing, there was a lot of cache aliasing going > > on leading to inefficient cache usage and redundant memory operations. > > > > When the same workload on Linux was run on FreeBSD but with the Linux > > library/allocators, the performance was identical. > > > > No-one followed through. I think I may have to write a blog post about > it. > > There's no MALLOC_OPTIONS flag to set/unset this, but adding a new flag to > disable a feature is easier (or should be) than implementing new one. The > only problem I see to this is if the cache align happens at sbrk/mmap level. > > > > > > -adrian > > _______________________________________________ > > freebsd-questions@freebsd.org mailing list > > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > > To unsubscribe, send any mail to " > freebsd-questions-unsubscribe@freebsd.org" > > > --- --- > Eduardo Morras > _______________________________________________ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " > freebsd-questions-unsubscribe@freebsd.org" >