Messages in this thread | | | Date | Thu, 18 Jul 2002 14:14:26 +0200 | From | David Balazic <> | Subject | Re: [PATCH] IDE TCQ |
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On Mon, Apr 15 2002, Jens Axboe wrote: > On Mon, Apr 15 2002, Jens Axboe wrote: > > On Mon, Apr 15 2002, Aaron Tiensivu wrote: > > > Simple question but hopefully it has a simple answer.. is there a command > > > you can issue or flag you can look for from the output of hdparm to tell if > > > your hard drive is capable of TCQ before installing the patch? I have a few > > > IBM drives that I'm sure have TCQ abilities but I don't trust them as far as > > > I can throw them (being Hungarian and cursed) but I'd like to give TCQ a > > > whirl on my WD 120GB drives that should work OK, if they support TCQ.. > > > > > > Sorry if it's already been asked.. :) > > > > It has not been asked :-) > > > > You can run a IDENTIFY_DEVICE from user space with the task ioctls and > > look at word 83 -- bit 1 and 14 must be set for TCQ to be supported. If > > you give me the model identifier from the IBM drive, I can tell you if > > it has tcq or not... > > > > I'll write a small util to detect this tomorrow and send it to you + the > > list. > > Duh, you can of course just look at /proc/ide/ideX/hdY/identify and > parse that. The info above is still valid for that, of course :-)
Recent versions of hdparm ( 4.x like shipped with recent redhat linux ) give a nice report about this :
hdparm -I /dev/hda ( or maybe it is the -i option )
Interestingly , on my system it also says that both my ATAPI CD-ROMs ( one is a CD-RW : Acer 1208A , the other is a CD-ROM : Teac CDR-532E-B ) support ATA command overlap ( maybe queuing too, I don't recall right now ).
Is overlapping supported in current TCQ code ? If not, will it be ?
It would be cool to access one drive in the seconds while the other tries to read a sector ( time from sending the read command, disc spinning up, reading and delivering the sector can be up to 2 seconds ! )
Best regards, david balazic - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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