AW: AW: Block Cache

Stefan Kalkowski stefan.kalkowski at ...1...
Wed Apr 30 11:12:22 CEST 2014 

Hi,

On 04/29/2014 11:55 AM, Wolfgang Schmidt wrote:
> Hi,
> 
> The last time the build Problem was mit on Hardware, but on building it
> with the run/Demo for qemu.
> 
> This now works after the comments.
> 
> What haven't worked right now is using the live cd on real hardware. (
> neither older L4 mir newer Linux live Demo)
> So I asked to know wether a specific Plattform is known to work as I
> habe no Nova knowledge so far ( to reduce the risk of asking to many
> stupid questions).
> 
> Of I understand You correctly the was of using a filesystem with cache
> wozld be
> 
> ahci as driver -> blockcache as server -> rump_fs as single client of
> the blockcache and as server for -> multiple programs accessing files.
> 
> Is this correct?

Although I'm not sure, whether I've understood your mail correctly, your
last statement regarding the possible usage of the block cache is correct.

Regards
Stefan

> 
> Best regards
> Wolfgang
> ------------------------------------------------------------------------
> Von: Stefan Kalkowski <mailto:stefan.kalkowski at ...1...>
> Gesendet: ‎29.‎04.‎2014 09:37
> An: genode-main at lists.sourceforge.net
> <mailto:genode-main at lists.sourceforge.net>
> Betreff: Re: AW: Block Cache
> 
> Hi Wolfgang
> 
> On 04/28/2014 10:25 PM, Wolfgang Schmidt wrote:
>> Hi Stefan,
>> Can You give a gibt for compatible x86 hw? I tried The democd on an FSC
>> Athlon64 which did mit start at all. Does for example a comp list for
>> nova exist?
> 
> No, I've no compatibility list available. I know of quite different
> Intel PCs people are using doing experiments with Genode/NOVA.
> 
> What do you mean with it didn't start at all on your specific hardware?
> The last time I've read an email from you regarding problems with NOVA
> on real hardware, it failed to compile the framebuffer driver, because
> your third-party-code "libports" repository probably wasn't prepare
> accordingly. Maybe it's better to smooth build problems out, instead of
> searching for new hardware?
> 
>>
>> What so You mean with: it serves only one client- one client application?
> 
> I meant, the block cache acts like a block driver. In general a block
> driver in Genode serves only one client, e.g.: a filesystem server. If
> you want to share the same device with multiple clients, you might use
> the "part_blk" server, which provides different partitions, found on the
> device, as separate block sessions to different clients.
> 
> Does that clarifies your question?
> 
> Regards
> Stefan
> 
>>
>> Best regards
>> Wolfgang
>> ------------------------------------------------------------------------
>> Von: Stefan Kalkowski <mailto:stefan.kalkowski at ...1...>
>> Gesendet: ‎28.‎04.‎2014 21:13
>> An: genode-main at lists.sourceforge.net
>> <mailto:genode-main at lists.sourceforge.net>
>> Betreff: Re: Block Cache
>>
>> Hi Wolfgang,
>>
>> On 04/28/2014 08:27 PM, w_schmidt at ...181... wrote:
>>> Hello,,
>>>
>>> I have a few question regarding genodes block cache in 14.02.
>>>
>>> If understand it correctly on x86-based computers genode starts on top of
>>> linux.
>>
>> well, that's not true. Yes, Genode is able to run on top of Linux,
>> mostly for development purposes. But Genode runs also directly on x86
>> hardware using the NOVA kernel, or Fiasco.OC kernel, or the OKL4 kernel,
>> or Pistachio kernel.
>>
>>> Therefore multiple caches will be used before something goes to genode
>>> a) the cache on a hdd
>>> b) cache on a drive controller
>>> c) the linux block cache
>>
>> If running on Linux yes, but normally it wouldn't make much sense to use
>> an additional block cache here.
>>
>>> d) qemu
>>
>> As already said: you don't need to use Qemu. Most run scripts are
>> starting Qemu by default, for convenience reasons only.
>>
>>>
>>> The first one is about the scenario in which the block cache is used.
>>> Is the block cache only thought for embedded devices where genode runs
>>> nativly? Are all embeded devices usable with the cache?
>>
>> The block cache uses the block session of Genode. It uses exactly one
>> block device, and serves exectly one client. As all block device drivers
>> of Genode are implementing the block session interface, the block cache
>> can be used on top of all block drivers, whether its a x86 AHCI driver,
>> or MMC card driver of an ARM SoC, or whatever.
>>
>>>
>>> Is there a way to mount a partition in genode with qemu without using
>> caches
>>> from c) and d) ?
>>> Or is there a x86 hardware where genode can directly operate on?
>>
>> Qemu allows to define the caching policy of a hard drive (cache=none). I
>> don't know whether it's possible to circumvent Linux block cache. I
>> assume that's hard.
>> But as mentioned above, you can use conventional x86 PC hardware.
>>
>> Regards
>> Stefan
>>
>>>
>>> As far as I have seen so far the disc cache of Linux does not seem to be
>>> disablable. I have only foudn ways to flush linux cache (like sync &&
>> echo 3
>>>  > /proc/sys/vm/drop_caches).
>>>
>>> Best regards,
>>> Wolfgang
>>>
>>>
>>>
>>
> ------------------------------------------------------------------------------
>>> "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE
>>> Instantly run your Selenium tests across 300+ browser/OS combos.  Get
>>> unparalleled scalability from the best Selenium testing platform
>> available.
>>> Simple to use. Nothing to install. Get started now for free."
>>> http://p.sf.net/sfu/SauceLabs
>>> _______________________________________________
>>> Genode-main mailing list
>>> Genode-main at lists.sourceforge.net
>>> https://lists.sourceforge.net/lists/listinfo/genode-main
>>>
>>
>> --
>> Stefan Kalkowski
>> Genode Labs
>>
>> http://www.genode-labs.com/ · http://genode.org/
>>
>>
> ------------------------------------------------------------------------------
>> "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE
>> Instantly run your Selenium tests across 300+ browser/OS combos.  Get
>> unparalleled scalability from the best Selenium testing platform
> available.
>> Simple to use. Nothing to install. Get started now for free."
>> http://p.sf.net/sfu/SauceLabs
>> _______________________________________________
>> Genode-main mailing list
>> Genode-main at lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/genode-main
>>
>>
>>
> ------------------------------------------------------------------------------
>> "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE
>> Instantly run your Selenium tests across 300+ browser/OS combos.  Get
>> unparalleled scalability from the best Selenium testing platform
> available.
>> Simple to use. Nothing to install. Get started now for free."
>> http://p.sf.net/sfu/SauceLabs
>>
>>
>>
>> _______________________________________________
>> Genode-main mailing list
>> Genode-main at lists.sourceforge.net
>> https://lists.sourceforge.net/lists/listinfo/genode-main
>>
> 
> -- 
> Stefan Kalkowski
> Genode Labs
> 
> http://www.genode-labs.com/ · http://genode.org/
> 
> ------------------------------------------------------------------------------
> "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE
> Instantly run your Selenium tests across 300+ browser/OS combos.  Get
> unparalleled scalability from the best Selenium testing platform available.
> Simple to use. Nothing to install. Get started now for free."
> http://p.sf.net/sfu/SauceLabs
> _______________________________________________
> Genode-main mailing list
> Genode-main at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/genode-main
> 
> 
> ------------------------------------------------------------------------------
> "Accelerate Dev Cycles with Automated Cross-Browser Testing - For FREE
> Instantly run your Selenium tests across 300+ browser/OS combos.  Get 
> unparalleled scalability from the best Selenium testing platform available.
> Simple to use. Nothing to install. Get started now for free."
> http://p.sf.net/sfu/SauceLabs
> 
> 
> 
> _______________________________________________
> Genode-main mailing list
> Genode-main at lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/genode-main
> 

-- 
Stefan Kalkowski
Genode Labs

http://www.genode-labs.com/ · http://genode.org/

More information about the users mailing list