From mboxrd@z Thu Jan 1 00:00:00 1970 MIME-Version: 1.0 In-Reply-To: <21b55d1c3bb01fa55e90f9400a0cdfb1@quanstro.net> References: <3aaafc130903032105i742648d2o86ccd2630c4aa61c@mail.gmail.com> <21b55d1c3bb01fa55e90f9400a0cdfb1@quanstro.net> Date: Wed, 4 Mar 2009 11:52:16 -0500 Message-ID: <3aaafc130903040852h691b8742t2052e61334c825eb@mail.gmail.com> From: "J.R. Mauro" To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Subject: Re: [9fans] threads vs forks Topicbox-Message-UUID: b165cf3c-ead4-11e9-9d60-3106f5b1d025 On Wed, Mar 4, 2009 at 12:50 AM, erik quanstrom wro= te: >> > >> > Both AMD and Intel are looking at I/O because it is and will be a limi= ting >> > factor when scaling to higher core counts. > > i/o starts sucking wind with one core. > that's why we differentiate i/o from everything > else we do. > >> And soon hard disk latencies are really going to start hurting (they >> already are hurting some, I'm sure), and I'm not convinced of the >> viability of SSDs. > > i'll assume you mean throughput. =A0hard drive latency has been a big dea= l > for a long time. =A0tanenbaum integrated knowledge of track layout into > his minix elevator algorithm. Yes, sorry. > > i think the gap between cpu performance and hd performance is narrowing, > not getting wider. > > i don't have accurate measurements on how much real-world performance > difference there is between a core i7 and an intel 5000. =A0it's generall= y not > spectacular, clock-for-clock. on the other hand, when the intel 5000-seri= es > was released, the rule of thumb for a sata hd was 50mb/s. =A0it's not too= hard > to find regular sata hard drives that do 110mb/s today. =A0the ssd drives= we've > (coraid) tested have been spectacular --- reading at > 200mb/s. =A0if you= want > to talk latency, ssds can deliver 1/100th the latency of spinning media. > there's no way that the core i7 is 100x faster than the intel 5000. For the costs (in terms of power and durability) hard drives are really a pain, not just for some of the companies I've talked to that are burning out terabyte drives in a matter of weeks, but for "mere mortals" as well. And I'm sorry but the performance of hard drives is *not* very good, despite it improving. Every time I do something on a large directory tree, my drive (which is a model from last year) grinds and moans and takes, IMO, too long to do things. Putting 4GB of RAM in my computer helped, but the buffering algorithms aren't psychic, so I still pay a penalty the first time I use certain directories. Now I haven't tested an SSD for performance, but I know they are better. If I got one, this problem would likely subside, but I'm not convinced that SSDs are durable enough, despite what the manufacturers say. I haven't seen many torture tests on them, but the fact that erasing a block destroys it a little bit is scary. I do a lot of sustained writes with my typical desktop workload over the same files, and I'd rather not trust them to something that is delicate enough to need filesystem algorithms to be optimized for so they don't "wear out". I guess, in essence, I just want my flying car today. > > - erik > >