Hi Philipp, On 03/24/2017 09:47 AM, Philipp Kerling wrote: > Hi, > > 2017-03-21 (火) の 10:49 +0100 に Sebastian Sumpf さんは書きました: >>> Do you have any specific feature >>> requests besides simple read/write? >> >> Read/write with native command queuing support would suffice. > NCQ isn't directly applicable to NVMe, at least not in the SATA sense. > NVMe has mandatory support for 65535 distinct submission queues into > which you can each put 65536 commands that are executed in no > particular order (i.e. possibly in parallel and as the controller sees > fit, similarly to NCQ). > For Genode, using one queue would probably be sufficient. > This does mean that the NVMe driver has to make sure that if you e.g. > get a write and then a read of the same address queued from an > application, the read would have to be postponed until the write is > completed since the NVMe controller does not guarantee in-order > execution. Now that I think about it though, this also applies to SATA > NCQ and is what I guess Ata_driver::overlap_check() is for in the AHCI > driver.
Good research from your side here. > >> If the above is working, it would be interesting to investigate if >> there >> are features Genode could benefit from and maybe implement some. >> Additionally power management is always a topic. > Ok thanks, noted. Does Genode have support for ACPI device power state > switching, particularly Runtime D3? No, power management is still in its infancy. But this is a topic the Genode staff will have to work on. > NVMe also supports elaborate PM, some of which (e.g. automatic PM) > could easily be integrated. The more involved stuff depends a lot on > knowing the workload and requirements of the system (i.e. burstiness, > priority of latency or throughput, ...), but that could be made into > parameters provided to the driver. Sounds good, looking forward to your proposal. Sebastian -- Sebastian Sumpf Genode Labs http://www.genode-labs.com · http://genode.org Genode Labs GmbH · Amtsgericht Dresden · HRB 28424 · Sitz Dresden Geschäftsführer: Dr.-Ing. Norman Feske, Christian Helmuth ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot _______________________________________________ genode-main mailing list genode-main@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/genode-main
