Path: csiph.com!v102.xanadu-bbs.net!xanadu-bbs.net!feeder.erje.net!eu.feeder.erje.net!news.albasani.net!.POSTED!not-for-mail From: aminer Newsgroups: comp.programming.threads,comp.programming Subject: Scalability and hashtables and databases Date: Mon, 21 Oct 2013 17:29:22 -0700 Organization: albasani.net Lines: 27 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Trace: news.albasani.net +G8bAunaMVdKeUydMXbXIfV7hIWTJTXKPFUgvom8k5prI/zbwD4th5ZdHf0jhWTzXY7H5nVYD6xEYZAMt+tase/g4QRgcWhnqBqMHTH/CVLP2W9gOBD3m/BbuK0/lVrY NNTP-Posting-Date: Mon, 21 Oct 2013 21:29:15 +0000 (UTC) Injection-Info: news.albasani.net; logging-data="FZhl9X1LVDr9PvmDUIjeO395jeCUjkr906Xm0yG6jUB5GnU0dlqqn2OCzoGCmeey4tWTLGwAQLITP20tFKavOhGR+EiD0Ipb2mS7qAYhT0Yi19fNhfoc++f/kxvON6Lx"; mail-complaints-to="abuse@albasani.net" User-Agent: Mozilla/5.0 (Windows NT 6.0; WOW64; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 Cancel-Lock: sha1:15vxg7bUvhXe4DoRSQ2gTG0S1I4= Xref: csiph.com comp.programming.threads:1944 comp.programming:3958 Hello, I come to an interresting subject, i want to talk about the scalability on multicores of the parallel hashtables and databases engines... i am wondering how can you say that a parallel hashtable can scale on multicores if the random key acesses are cache unfreiendly and the parallel hashtable is memory bound ? i think since the parallel hashtable is memory bound and the random accesses are cache unfreindly that means that the parallel hashtable will not scale on multicores, when you are testing your parallel hashtable, you have also to test the cache misses on the data, cause i think that the data is part of the hashtable application, i mean the parallel hashtable concept is highly interconnected with the way that the data is accessed randomly in a cache unfreindly manner and the hashtables concept is is highly interconnected with the way the hashtable data is accessed in memory bound manner, so this why i say that parallel hashtables are not scalable on multicores, it's the same for database engines , since they are disk bound, so they are not scalable, and even if they are in-memory databases they will be memory bound and cache unfreindly, so databases are not scable either on mutilcores. Thank you, Amine Moulay Ramndane