L1 read data evicted upon L2 write

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RobF99
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L1 read data evicted upon L2 write

Post by RobF99 »

I was running my L1 with 100% Read and 0% write and my L2 Read/Write. I noticed that Read data that was in L1 would be evicted if that data was written to L2. Was I imagining this, or is this the expected behavior given those settings? It would be nice if there was a way to prevent this behavior. The reason I like to use this setting is that if I have L1 as R/W then any write data does not get cached unless it is read. I like to have it cached on L2. I usually have a pretty big outlook.pst file and I find that the entire file is not always fully cached if I have L1 as R/W because new e-mails etc do not get cached if that part of the file is written to and the .pst file grows.

I did submit a request that you automatically L2 cache any L1 write data because it is not expensive, and you do have that for a future build. Maybe at that time the problem above will be addressed as part of that tweak.
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Re: L1 read data evicted upon L2 write

Post by Support »

RobF99 wrote: Fri Jul 09, 2021 8:22 pm I noticed that Read data that was in L1 would be evicted if that data was written to L2.
No. PrimoCache evicts L1 data based on L1 algorithm, not related to L2. Hot data will dislike to be evicted.
RobF99
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Re: L1 read data evicted upon L2 write

Post by RobF99 »

Can I ask a variation on this question? Let us say I have L1 50% R/W. If there is L1 Write data that gets read a few times and becomes hot. Does that now become counted so that it changes Free L1 read cache does it remain in L1 write? In other words, assume it is 1 Gb, when it is read and becomes hot data does Free L1 R reduce by 1 Gb and Free write increase by 1 Gb?
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Re: L1 read data evicted upon L2 write

Post by Support »

Good question! Which cache space data stay is determined by the first time of access. So if a write block gets read later, it still stay in the write cache space.
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