[haiku-development] Re: EeePC networking
- From: "David Weizades" <ddewbofh@xxxxxxxxx>
- To: haiku-development@xxxxxxxxxxxxx
- Date: Mon, 15 Dec 2008 14:43:55 +0100
On Mon, Dec 15, 2008 at 2:14 PM, Axel Dörfler <axeld@xxxxxxxxxxxxxxxx> wrote:
> "Fredrik Holmqvist" <fredrik.holmqvist@xxxxxxxxx> wrote:
>> 2008/12/15 Axel Dörfler <axeld@xxxxxxxxxxxxxxxx>:
>> > Just check out the Haiku tree, and you will notice that the whole
>> > thing
>> > freezes from time to time, and I don't believe it's a hardware only
>> > problem (and I've noticed those hangs on other platforms as well,
>> > just
>> > not as impressive).
>> Maybe it's the problem with random writes on SSD's (all but the new
>> Intel based), which matches that description quite well.
>
> It's perfectly acceptable for a write operation to take its time - but
> it's not acceptable to have the whole system hang as a result.
>
> Bye,
> Axel.
>
>
>
This is not so much a problem with SSDs in general but with the two
different variants
and cache. We have SLC (single layer) and MLC (multi level) where SLC
is faster, safer
but also a lot more expensive. Then we have the whole cache issue,
without a decent
write cache all SSD's are incredibly slow, the more expensive makes
like Intel and MICRON
have a built-in cache. There are also reasons why a 64GB SLC SSD cost
as much as, if not
more than a 128GB MLC drive. Once you have a sane write cache, be it
software or hardware
then SSD's are incredibly fast. It took some time and effort to get it
working fine but now my
single SSD outperforms my previous RAID-0 array with 10K rpm
SCSI-drives. RAID still is faster
on throughput but the random access time with flash means much more on
a desktop than
massive bandwidth.
Cheers
David
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