Background movers implementation #352
Open
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
facebook-github-bot
added
the
CLA Signed
byrnedj
force-pushed
the
background_movers
branch
from
0bd6746 to
7105800
Compare
This is the implementation logic for the background eviction (and promotion when multi-tier is enabled). The main parameters for the background workers are the number of threads, `backgroundMoverThreads` and the batch size used `backgroundEvictionBatch`, which configures the number of items to evict in batch (while holding the container lock), and `backgroundTargetFree` which sets target free percentage of each class. The background workers will work to keep that percentage of space free. The main result is that SET (allocate) latencies are significantly reduced - kvcache workload with 40GB DRAM, ampFactor set to 200 via the trace replayer. Throughput set at 1.2M ops/sec. | Percentile | % Improvement | |------------|---------------| | 0.50000 | 70.4 | | 0.90000 | 23.0 | | 0.99000 | 12.2 | | 0.99900 | 89.7 | | 0.99990 | 24.9 | | 0.99999 | 0.6 | The GET (find) latencies are unaffected by the background workers as long as the batch size remains reasonably small (10 in our tests).
byrnedj
force-pushed
the
background_movers
branch
from
7105800 to
95fc453
Compare
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This is the implementation logic for the background eviction (and promotion when multi-tier is enabled).
We benchmarked the background evictors against the current upstream branch with the following configurations using the kvcache workload and the trace replayer. Throughput was kept constant - 1.2M ops/sec using DRAM-only 40GB cache size with ampFactor set to 200. The config files are attached.
The main parameters for the background workers are the number of threads,
backgroundMoverThreadsand the batch size usedbackgroundEvictionBatch, which configures the number of items to evict in batch (while holding the container lock), andbackgroundTargetFreewhich sets target free percentage of each class. The background workers will work to keep that percentage of space free.The main result is that SET (allocate) latencies are significantly reduced.
The GET (find) latencies are unaffected by the background workers as long as the batch size remains reasonably small (10 is the default).
baseline.json
bg-eviction.json