Bug 208174

Summary: Check NetworkProcess' cache policy
Product: WebKit Reporter: Yusuke Suzuki <ysuzuki>
Component: Page LoadingAssignee: Yusuke Suzuki <ysuzuki>
Status: NEW ---    
Severity: Normal CC: beidson
Priority: P2    
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   

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.