Re: Building computer
On 9/27/2013 6:03 AM, Joel Rees wrote:
> On Fri, Sep 27, 2013 at 10:22 AM, Tom H <tomh0665@gmail.com> wrote:
>> On Thu, Sep 26, 2013 at 7:09 AM, Stan Hoeppner <stan@hardwarefreak.com> wrote:
>>> On 9/26/2013 5:45 AM, Joel Rees wrote:
>>>> On Thu, Sep 26, 2013 at 2:05 PM, Stan Hoeppner <stan@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.
> 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.
>
> (I sat on my Lenovo ideapad s100, and now I can only use it with the
> external monitor, so I'm a bit sensitive to sturdiness now. Not that I
> plan on sitting on any more computers, of course. Should not have
> taken the thing to church after programming all Saturday night. And,
> no, I have not been running qemu on the ideapad. It's a single-core
> Atom. Bleagh.)
>
>> I'm pretty sure that I've seen a thread where kernel developers (Linus
>> included) who were discussing kernel compilation time on laptops.
>
> Thanks for the data points, Tom.
>
>> (I've compiled a kernel on a netbook; you'd better have a few hours to spare...)
>
> That's a given. I'm not planning on compiling the kernel every day,
> but I will be compiling loadable modules, cross or under emulation,
> pretty regularly, at some point
> --
> Joel Rees
>
> Be careful where you see conspiracy.
> Look first in your own heart.
>
>
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