Re: Building a computer for compiling and CPU emulation (Re: Building computer)
On 10/1/2013 9:16 AM, Joel Rees wrote: On Tue, Oct 1, 2013 at 7:00 AM, Stan Hoeppner s...@hardwarefreak.com wrote: On 9/29/2013 6:01 AM, Joel Rees wrote: ... http://en.wikipedia.org/wiki/List_of_AMD_mobile_microprocessors tells me that AMD A4-1250, AMD A6-1450, and E2-1800 all have AMD-V. The E2-1800 has a half-Meg L2 cache, but higher speed CPU (1.7GHz). The A4-1250 has 1 Meg L2 cache but lower speed CPU (1.0 GHz). The A6-1450 has 2 Meg L2 cache to share between twice the CPUs. The A4-1450 is probably the best choice, not taking cost into consideration. Here's why: 1. Turbo core up to 1.4GHz 2. All 3 models have 512KB L2/core, no advantage for any 3. Temash core has better IPC than Zacate 4. 4 cores @ 1.4GHz should give better compile times than 2 cores @ 1.8GHz. 4 @ 1GHz should as well. -j4 or higher 5. A6-1450 is 9W chip, E2-1800 is 18W chip, longer run time 28nm vs 40nm The one downside is that for non-compute intensive operations, such as normal interactive GUI apps, say PDF viewing, browser rendering, etc, it may be considerably slower than the 1.8GHz E2-1800, due to the 800MHz clock deficit, as the turbo core may not kick in a lot here. And WRT turbo core, I'm not quite sure what this means: Selected parts support Turbo Dock technology, that can increase CPU and GPU frequencies when external cooling is available. So if the unit you purchase doesn't have a variable speed fan that can fulfill this requirement, this may mean you can't get 1.4GHz turbo mode. And I'm just guessing that devices of this class may not include forced air cooling. Sorry I don't have all the answers here, but maybe this helps get you a bit closer. One thing I can assure you of is that for your stated use case, IIUI correctly, all of these CPUs are very likely woefully inadequate for the task. Yes and no. Most of the compiling will be much smaller than a kernel, not even complete packages. I think I said it but you've clipped that part, but this is a course in programming that includes writing some drivers. Got it. Yeah, compiling a few hundred or thousand lines of code shouldn't be that bad. Emulating the superH processor is going to be a bit demanding, Instruction set level emulation is going to be extremely demanding if you intend to run a complete emulated OS environment. If you strictly use it for things like executing and debugging individual subroutines, code segments, etc, it shouldn't be too bad. particularly if I find myself wanting to compile a superH kernel and not having access to the school labs over a long holiday. I am aware of that and will plan accordingly. Yep. Mostly, I was trying to dig up the AMD-V support and something in the thread pointed me the right direction. Having AMD-V or Intel VT isn't an absolute requirement. Both will speed up context switches. As important as the new thread switching hardware in these CPUs is the size of the TLBs. CPUs without virtualization support tend to have inadequate TLBs. When you switch between VMs you end up flushing most of the TLB entries and reloading them. CPUs with large L2/L3 caches help mitigate this to a degree. Which is one of the reasons you see ginormous caches on server oriented CPUs, Xeon and Opteron, up to 34MB combined L2/L3. Most server workloads are transaction oriented and throughput is dictated by network/disk latency. A huge cache does nothing for you here. But when you run many virtual machines it provides serious benefit. This is one of the reasons I recommended going for the largest cache you can get. Unfortunately there's not much difference in cache sizes in the processor class you're looking at. Have you considered a refurb or used laptop? The Core2 Duo SL9600 offers 2.13GHz clock, 6MB L2 cache, at 17W. The Mobile PhenomII P650 2.6GHz clock w/2MB L2, 25W. I'm not planning getting more than AMD-V in a portable machine. Don't want to carry a boat battery with me. :-p Heheh, love the deep cycle reference. Though if you're like many mobile users, in the States anyway, most of the time a wall plug isn't far away, in either distance or time. Never visited Japan so I can comment on the situation there. -- Stan -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/524bc151.9070...@hardwarefreak.com
Re: Building a computer for compiling and CPU emulation (Re: Building computer)
On Tue, Oct 1, 2013 at 7:00 AM, Stan Hoeppner s...@hardwarefreak.com wrote: On 9/29/2013 6:01 AM, Joel Rees wrote: ... http://en.wikipedia.org/wiki/List_of_AMD_mobile_microprocessors tells me that AMD A4-1250, AMD A6-1450, and E2-1800 all have AMD-V. The E2-1800 has a half-Meg L2 cache, but higher speed CPU (1.7GHz). The A4-1250 has 1 Meg L2 cache but lower speed CPU (1.0 GHz). The A6-1450 has 2 Meg L2 cache to share between twice the CPUs. The A4-1450 is probably the best choice, not taking cost into consideration. Here's why: 1. Turbo core up to 1.4GHz 2. All 3 models have 512KB L2/core, no advantage for any 3. Temash core has better IPC than Zacate 4. 4 cores @ 1.4GHz should give better compile times than 2 cores @ 1.8GHz. 4 @ 1GHz should as well. -j4 or higher 5. A6-1450 is 9W chip, E2-1800 is 18W chip, longer run time 28nm vs 40nm The one downside is that for non-compute intensive operations, such as normal interactive GUI apps, say PDF viewing, browser rendering, etc, it may be considerably slower than the 1.8GHz E2-1800, due to the 800MHz clock deficit, as the turbo core may not kick in a lot here. And WRT turbo core, I'm not quite sure what this means: Selected parts support Turbo Dock technology, that can increase CPU and GPU frequencies when external cooling is available. So if the unit you purchase doesn't have a variable speed fan that can fulfill this requirement, this may mean you can't get 1.4GHz turbo mode. And I'm just guessing that devices of this class may not include forced air cooling. Sorry I don't have all the answers here, but maybe this helps get you a bit closer. One thing I can assure you of is that for your stated use case, IIUI correctly, all of these CPUs are very likely woefully inadequate for the task. Yes and no. Most of the compiling will be much smaller than a kernel, not even complete packages. I think I said it but you've clipped that part, but this is a course in programming that includes writing some drivers. Emulating the superH processor is going to be a bit demanding, particularly if I find myself wanting to compile a superH kernel and not having access to the school labs over a long holiday. I am aware of that and will plan accordingly. Mostly, I was trying to dig up the AMD-V support and something in the thread pointed me the right direction. I'm not planning getting more than AMD-V in a portable machine. Don't want to carry a boat battery with me. :-p -- Joel Rees Be careful where you see conspiracy. Look first in your own heart. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/CAAr43iOfa495=zs8ezdry1hnjv_bi39_ckvvrgzrs2zwero...@mail.gmail.com
Re: Building a computer for compiling and CPU emulation (Re: Building computer)
On 9/29/2013 6:01 AM, Joel Rees wrote: ... http://en.wikipedia.org/wiki/List_of_AMD_mobile_microprocessors tells me that AMD A4-1250, AMD A6-1450, and E2-1800 all have AMD-V. The E2-1800 has a half-Meg L2 cache, but higher speed CPU (1.7GHz). The A4-1250 has 1 Meg L2 cache but lower speed CPU (1.0 GHz). The A6-1450 has 2 Meg L2 cache to share between twice the CPUs. The A4-1450 is probably the best choice, not taking cost into consideration. Here's why: 1. Turbo core up to 1.4GHz 2. All 3 models have 512KB L2/core, no advantage for any 3. Temash core has better IPC than Zacate 4. 4 cores @ 1.4GHz should give better compile times than 2 cores @ 1.8GHz. 4 @ 1GHz should as well. -j4 or higher 5. A6-1450 is 9W chip, E2-1800 is 18W chip, longer run time 28nm vs 40nm The one downside is that for non-compute intensive operations, such as normal interactive GUI apps, say PDF viewing, browser rendering, etc, it may be considerably slower than the 1.8GHz E2-1800, due to the 800MHz clock deficit, as the turbo core may not kick in a lot here. And WRT turbo core, I'm not quite sure what this means: Selected parts support Turbo Dock technology, that can increase CPU and GPU frequencies when external cooling is available. So if the unit you purchase doesn't have a variable speed fan that can fulfill this requirement, this may mean you can't get 1.4GHz turbo mode. And I'm just guessing that devices of this class may not include forced air cooling. Sorry I don't have all the answers here, but maybe this helps get you a bit closer. One thing I can assure you of is that for your stated use case, IIUI correctly, all of these CPUs are very likely woefully inadequate for the task. -- Stan -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/5249f491.4090...@hardwarefreak.com
Building a computer for compiling and CPU emulation (Re: Building computer)
On Sun, Sep 29, 2013 at 1:59 AM, Stan Hoeppner s...@hardwarefreak.com wrote: On 9/27/2013 6:03 AM, Joel Rees wrote: On Fri, Sep 27, 2013 at 10:22 AM, Tom H tomh0...@gmail.com wrote: On Thu, Sep 26, 2013 at 7:09 AM, Stan Hoeppner s...@hardwarefreak.com wrote: On 9/26/2013 5:45 AM, Joel Rees wrote: On Thu, Sep 26, 2013 at 2:05 PM, Stan Hoeppner s...@hardwarefreak.com wrote: On 9/25/2013 12:52 PM, Catherine Gramze wrote: Stan, joking aside, are there any AMD processors you would recommend for doing kernel and driver level Android/ARM development in a VM? How likely would I be to find such a processor in a netbook or laptop? How likely is one to find a kernel developer doing any real work on a laptop? Throwing a netbook into the question is just silly. The reason I ask, Stan, is that I'm preparing to take a class where I'll be studying Super H assembly language programming, writing device drivers for an embedded SH3 running a Linux kernel, and such. I read everything below but my reply will be brief, so going up top with it. Performance options with portables is always limited due to power. A few quick points: 1. If you're going to be compiling anything, cache size trumps clock speed. If a smaller cache roughly equivalent CPU clocks more than ~30% higher than big_cache CPU it becomes a horse race. 2. Do not use an in-order CPU, such as the Atom, regardless of clock speed. The lack of branch prediction, rename registers, etc, will hamstring a compiler. 3. If you're running a hypervisor, low level support such as AMD-V or Intel VT will help. Okay, ... I'd like to prepare a portable emulation environment for the class, since I know I'll be wanting to do homework when the lab is not available. Renasas points to an SH4 emulator by Kawasaki-san that runs under QEMU, but at times I will likely be debugging the emulator as well as my own code. And I'll be doing a lot of compiles in the emulated system. I'll be biking to the class some days and walking other days, so I'd like a 12 inch screen form factor to fit in my bag and not break my back, which pretty much says netbook. Many netbooks have output for external monitors, which will help at home, at least. At this point, I've been kind of looking at Acer's Aspire (heh) V5-122 with an AMD A4-1250 and 4G RAM, or a similar V5 with an AMD A6-1450. I'm trying to figure out whether they support QEMU. If so, I'm thinking the 4-core A6 will be worth the extra 5000 yen, a pair of core for the host OS and I/O, and another core for the emulation environment makes three. I'm also looking at an HP dm1-4400, but the processor there is an AMD E2-1800, which seems to be last year's tech and a little heavier on battery use. It's only two cores, and only 2G RAM in the version at the store where I was looking at it (Sofmap in Umeda -- Osaka), but maybe HP is sturdier than Acer. I need to look at that. http://en.wikipedia.org/wiki/List_of_AMD_mobile_microprocessors tells me that AMD A4-1250, AMD A6-1450, and E2-1800 all have AMD-V. The E2-1800 has a half-Meg L2 cache, but higher speed CPU (1.7GHz). The A4-1250 has 1 Meg L2 cache but lower speed CPU (1.0 GHz). The A6-1450 has 2 Meg L2 cache to share between twice the CPUs. [...] So now my problem is scraping up 55,000 yen +/-. -- Joel Rees Be careful where you see conspiracy. Look first in your own heart. -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of unsubscribe. Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/caar43invbf8mexjrkeabjhcwnk6jsfo-sswp0ypreqsnwmw...@mail.gmail.com
