Parameter auto-tuning for the marginal-hits strategy

[hazelnut-99]

Summary

Added a new slabrebalance strategy: MarginalHitsStrategyNew, which builds upon the existing MarginalHitsStrategy. The goal is to mitigate slab thrashing issues by adding tuning mechanisms.

---

Different Strategy Configurations for Testing

The following configurations are supported and can be tested for performance comparison:

Option 1: Hits-Per-Slab

#include "cachelib/allocator/HitsPerSlabStrategy.h"

auto rbConfig = HitsPerSlabStrategy::Config{};
config.enablePoolRebalancing(
  std::make_shared<HitsPerSlabStrategy>(rbConfig),
  std::chrono::seconds(1));

---

Option 2: Marginal-Hits (Original) + Warm Tail + Cold Tail

#include "cachelib/allocator/MarginalHitsStrategy.h"

config.enableTailHitsTracking(); 
config.countColdTailHitsOnly = false;
auto rbConfig = MarginalHitsStrategy::Config{};
config.enablePoolRebalancing(
  std::make_shared<MarginalHitsStrategy>(rbConfig),
  std::chrono::seconds(1));

---

Option 3: Marginal-Hits (Original) + Cold Tail Only

#include "cachelib/allocator/MarginalHitsStrategy.h"

config.enableTailHitsTracking(); 
config.countColdTailHitsOnly = true;
auto rbConfig = MarginalHitsStrategy::Config{};
config.enablePoolRebalancing(
  std::make_shared<MarginalHitsStrategy>(rbConfig),
  std::chrono::seconds(1));

---

Option 4: Marginal-Hits-New (Tuned) + Warm Tail + Cold Tail

#include "cachelib/allocator/MarginalHitsStrategyNew.h"

config.enableTailHitsTracking(); 
config.countColdTailHitsOnly = false;
auto rbConfig = MarginalHitsStrategyNew::Config{};
config.enablePoolRebalancing(
  std::make_shared<MarginalHitsStrategyNew>(rbConfig),
  std::chrono::seconds(1));

---

Option 5: Marginal-Hits-New (Tuned) + Cold Tail Only

#include "cachelib/allocator/MarginalHitsStrategyNew.h"

config.enableTailHitsTracking(); 
config.countColdTailHitsOnly = true;
auto rbConfig = MarginalHitsStrategyNew::Config{};
config.enablePoolRebalancing(
  std::make_shared<MarginalHitsStrategyNew>(rbConfig),
  std::chrono::seconds(1));

---

Option 6: LRU-Tail-Age

#include "cachelib/allocator/LruTailAgeStrategy.h"

auto rbConfig = LruTailAgeStrategy::Config{};
config.enablePoolRebalancing(
  std::make_shared<LruTailAgeStrategy>(rbConfig),
  std::chrono::seconds(1));

[facebook-github-bot]

Hi @hazelnut-99!

Thank you for your pull request and welcome to our community.

Action Required

In order to merge any pull request (code, docs, etc.), we require contributors to sign our Contributor License Agreement, and we don't seem to have one on file for you.

Process

In order for us to review and merge your suggested changes, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

Once the CLA is signed, our tooling will perform checks and validations. Afterwards, the pull request will be tagged with CLA signed. The tagging process may take up to 1 hour after signing. Please give it that time before contacting us about it.

If you have received this in error or have any questions, please contact us at cla@meta.com. Thanks!

[facebook-github-bot]

Thank you for signing our Contributor License Agreement. We can now accept your code for this (and any) Meta Open Source project. Thanks!

[facebook-github-bot]

@pbhandar2 has imported this pull request. If you are a Meta employee, you can view this in D79255457.