Messages in this thread | | | Date | Sun, 16 Aug 2009 22:05:41 -0400 | From | Mark Lord <> | Subject | Re: Discard support (was Re: [PATCH] swap: send callback when swap slot is freed) |
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John Robinson wrote: .. > I'm slightly out of my depth here, but: if a single TRIM is issued, > which apparently returns quickly, can one then revert to issuing > ordinary commands like reads and writes and have them complete as > quickly as they normally do, or does any following command have to wait > until the trim completes? This could be useful if it turned out we won't > stall these devices as long as we don't issue more than one TRIM every > few seconds; we could keep a TRIM coalesce queue down to being (say) 5 > seconds long (or at least, a configurable small number of seconds). ..
I have not attempted to instrument that, but I suspect that any command after the TRIM has to wait. Don't know for sure until somebody measures it though.
One thing I do know, is that Matthew's first cut of TRIM support means it takes half an hour to do "rm -r" on a kernel source tree.
-ml
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