Charles,
Thanks for the quick reply.
I pulled all the Q&A to the top...
> Are you using Yaffs1 mode of operation? When a file is deleted the
> chunks are marked deleted and when all the chunks in a file are
> deleted, the erasure will occur. This can take some time.
Apparently I am... is_yaffs2 is not set.
Should this be set?
> There is some tuning, but perhaps a better option is to get a
> background thread going for doing the gc. This will clean the decks
> for writes to occur unimpeded.
I didn't see anything in the docs on implementing background garbage
collection when using CONFIG_YAFFS_DIRECT
> How full is the file system?
I've got 32Mbyte for storage, and about 6M used.
> Are you using the "soft delete" feature? This defers the actual
> deletion, but unless you have background gc running, this will just
> move the delays into the gc.
No, disable_soft_del is set to 1.
Anyway, it sounds like what I want to do here is enable soft-delete and
background garbage collection (separate task).
Is there any documentation on that?
Thanks much,
Ed
> Hello Ed
>
> NOR is very slow to erase and this is what is causing the issues.
>
>
> On Tue, May 6, 2014 at 6:15 AM, Ed Sutter
> <ed.sutter@alcatel-lucent.com <mailto:ed.sutter@alcatel-lucent.com>>
> wrote:
>
> Hi,
> I have YAFFS running in standalone mode for about a year now.
> My underlying memory is NOR, and generally speaking I see a
> write rate of about 1Mbyte every 3 seconds. I have not tuned
> the underlying flash accesses so I'm sure there's room for
> improvement there.
>
> The problem I am having is that as I add files (and remove them)
> I notice more and more that the 3 seconds turns into 10-15
> seconds occasionally. I assume yaffs is doing some garbage
> collection; however it seems to occure a lot more often than
> necessary. Is garbage collection likely the culprit? If yes,
> is there any tuning that can be done to adjust how often that
> is done?
>
>
> There is some tuning, but perhaps a better option is to get a
> background thread going for doing the gc. This will clean the decks
> for writes to occur unimpeded.
>
> How full is the file system?
>
>
> Also, is it correct to observe that the removal of a file takes
> essentially the same amount of time as adding a file?
>
>
> Are you using Yaffs1 mode of operation? When a file is deleted the
> chunks are marked deleted and when all the chunks in a file are
> deleted, the erasure will occur. This can take some time.
>
>
> Are you using the "soft delete" feature? This defers the actual
> deletion, but unless you have background gc running, this will just
> move the delays into the gc.
>
> Let's see what we can work out here.
>
> Regards
>
> Charles
>
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