How to get cache space freed up?

[erich56]

I installed PrimoCache a few days ago in order to reduce massive SSD writing by BOINC grid computing.
I made some strange observation though lately which I'd like to get clarified, just to make sure that my settings are correct (FYI, I have set L1 write caching only, no read caching, with "defer write" set to infinite):

Once the cache is filled with data ("free cache" is down to 32MB), any additional data is being written to the SSD - which I can see by watching that the values in "Total Write (req.)" and "Total Write (done)" go up by the same values. So far that's clear to me (BTW, cache size is 13GB, System RAM "left over" is 19GB - that turns out being best relation with regard to the tasks I am running).

However, what I realize is: obviously no data ever gets deleted from the cache, the value unter "free cache" always stays at 32MB.
Fact is that the BOINC Manager is normally deleting data which is no longer used once a WorkUnit gets finished. Depending on which tasks were crunched, the size of the BOINC data folder varies between some 6 and 15GB.
No other work is being done on this PC than BOINC.

So, my question is: which of the settings could I change in order to get cache space freed up once BOINC is deleting data?
As screenshot of how everything looks like is attached hereto.

[Support]

No need to free cache space. PrimoCache automatically discards old cache data and store new data.
I think your Windows OS is below to Windows 7/2008R2. For these OSes, TRIM command is not supported. When files are deleted, Windows doesn't notify disk which part of data can be removed. So PrimoCache still think data are needed and don't trim them.

[erich56]

Thanks for your quick Reply.
Indeed, my OS is below Win7. So I now performed a TRIM manually (using the tool included in the Samsung Magician). And I was assuming that after doing this, the value shown in "Free Cache" would increase from 32.00MB. But it did not. Is this still "normal" behaviour of PrimoCache, or is something wrong?

[erich56]

Following happened since I trimmed manually:
+ 7 GB for "Total Write req."
out of which 0,6 GB for "Urgent Write"
The size of the BOINC folder was and still is about 12.5 GB, i.e. 0,5 GB less than the Leve-1 Cache of 13 GB.
"Free Cache" still says 32.00 MB.

So my question: why were 0,6 GB (out of 7 GB total Write) written to SSD under "Urgent Write". Not really a big deal in terms of SSD wear (I do not worry), but I would just like to understand the concept behind PrimoCache (also: why are only 32.00MB shown as "Free Cache", although it should show more, and although I did perform trimming?)

[Support]

I don't think TRIM command issued Samsung Magician can do the function coming from Windows 7. Magician's TRIM command may be only for its SSD device. It cannot monitor Windows file deletion and do the corresponding work.

[JimF]

Once the TRIM issue is cleared up, the files should be removed from the cache as they are deleted by BOINC. My Win7 64-bit machine, rebooted a couple of days ago (which clears the cache), has a 16 GB cache, while the OS has written 22.58 GB. But I still have 13.18 GB cache memory that is free, with no Urgent writes to the SSD, so obviously files are being deleted.

[Support]

@JimF, yes, "Trimmed Blocks" indicates how many blocks were deleted from the cache.

[erich56]

so, understanding the facts correctly: running an OS below Win7, not "real" trimming will take place, thus never ever any blocks being deleted from the cache - is this assumption right?

[Support]

yes, at least Samsung Magician cannot do it.

[InquiringMind]

Once the TRIM issue is cleared up, the files should be removed from the cache as they are deleted by BOINC...

Actually, no they shouldn't. Doing so would require at least some extra CPU cycles (so you lose on performance) and you gain nothing since (if the cache was full) new data would still be allocated space taken from the least-used data in the cache.

In other items, the space "taken up" by deleted files in the cache will be automatically reused, without the need for further intervention.