Jens Axboe <axboe@xxxxxxx> writes: >> I'm not acquainted with kernel/block I/O queueing internals. > > SCSI without TCQ or with TCQ depth=1 should be safe, provided the driver > never reorders a command once it has received it. Wouldn't we rather use *deep* TCQ and set write cache enable to 0 then? Does anybody have benchmarks with TCQ depth = 1/WCE = 1 vs. TCQ = <deep> (64+)/WCE = 0? I only have ancient SCSI drives in test machines, so my testing wouldn't be representative. >> > > 2. for traditional IDE (such as VIA 82*, PIIX_*)? >> > >> > In SUSE kernels, for many years. Since 2.6.7/8'ish in Linus' kernels. >> >> I don't care for vendor kernels. Is listing 2.6.8 safe? > > Check the changelogs, I can't remember exactly if it was 2.6.7 or 2.6.8 > (or perhaps .6...). Hm. Any buzz^Wkeywords to look for? "barrier" doesn't seem to be the right word, it yields only memory barriers and an as-iosched fix in 2.6.7. I checked ChangeLog-2.6.[56789]. -- Matthias Andree - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
