Bug 208174 - Check NetworkProcess' cache policy
Summary: Check NetworkProcess' cache policy
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Page Loading (show other bugs)
Version: WebKit Nightly Build
Hardware: Unspecified Unspecified
: P2 Normal
Assignee: Yusuke Suzuki
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2020-02-24 19:36 PST by Yusuke Suzuki
Modified: 2020-02-25 00:28 PST (History)
1 user (show)

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Description Yusuke Suzuki 2020-02-24 19:36:21 PST
Membuster seems having several large CachedScript / CachedCSSStyleSheet Vectors, this sounds strange to me since it should be (hopefully) mapped as a mmap-ed file.
My guess is something pathological happens, but need to check what is preventing from caching for these resources.

1. It is possible that they are non-cached due to the right policy. In this case, we cannot get improvement.
2. It is possible that Membuster's memory-capturing timing is super quick and we get this data before NetworkProcess's notification replaces the content with mmap-ed file, this is possible.

But on the other hand,

1. It is possible that this is not cached due to wrong policy. We should double-check.
2. It is possible that this is not replaced with mmap-ed content due to wrong reason. We should double-check.
Comment 1 Yusuke Suzuki 2020-02-25 00:28:33 PST
It turned out that a lot of resources in old Membuster is rejected in NetworkCache because it does not include any expiration headers at all. So freshness becomes 0, and it is simply rejected.
But I think this is because old Membuster content is old... It would be true that new Membuster content has correct expiration header etc. and it caches things appropriately.