wcow-process: Query Stats directly from shim

[dcantah]

This change adds in functionality to query statistics directly in the shim instead of reaching out to HCS. One of the main motivators behind this was poor performance for tallying up the private working set total for the container in HCS.

HCS calls NtQuerySystemInformation with the class SystemProcessInformation which returns an array containing system information for every process running on the machine. They then grab the pids that are running in the container and filter down the entries in the array to only what's running in that silo and start tallying up the total. This doesn't work well as performance should get worse if more processes are running on the machine in general and not just in the container. All of the additional information besides the WorkingSetPrivateSize field is ignored as well which isn't great and is wasted work to fetch.

HCS only let's you grab statistics in an all or nothing fashion, so we can't just grab the private working set ourselves and ask for everything else separately. We can open the silo ourselves and do the same queries for the rest of the info, as well as calculating the private working set in a more efficient manner by:

1. Find the pids running in the silo
2. Get a process handle for every process (only need
   PROCESS_QUERY_LIMITED_INFORMATION access)
3. Call NtQueryInformationProcess on each process with the class
   ProcessVmCounters
4. Tally up the total using the field PrivateWorkingSetSize in
   VM_COUNTERS_EX2.

This change additionally:

• Changes the jobcontainers package to use this new way to calculate the
  private working set.
• Change the query the StorageStats method in the jobobject package uses
  to grab IO counters to match what HCS queries.

---

Some quick test results between grabbing the same stats inProc vs. calling PropertiesV2 and only asking for statistics:

PS C:\users\danny\go\src\github.com\microsoft\hcsshim\internal\jobobject> .\jobobject.test.exe '-test.v' '-test.run' TestStatsTime
=== RUN   TestStatsTimetest.v' '-test.run' TestStatsTime
Elapsed time for stats inproc: 2.3981ms

Memory: &{MemoryUsageCommitBytes:42471424 MemoryUsageCommitPeakBytes:75288576 MemoryUsagePrivateWorkingSetBytes:14024704}
Storage: &{ReadCountNormalized:106 ReadSizeBytes:849408 WriteCountNormalized:1337 WriteSizeBytes:9629696}
Processor: &{TotalRuntime100ns:133125000 RuntimeUser100ns:66562500 RuntimeKernel100ns:66562500}
--- PASS: TestStatsTime (0.00s)
=== RUN   TestStatsTime2
Elapsed time for stats from HCS: 13.6977ms

Memory: &{MemoryUsageCommitBytes:42471424 MemoryUsageCommitPeakBytes:75288576 MemoryUsagePrivateWorkingSetBytes:14024704}
Storage: &{ReadCountNormalized:106 ReadSizeBytes:849408 WriteCountNormalized:1337 WriteSizeBytes:9629696}
Processor: &{TotalRuntime100ns:133125000 RuntimeUser100ns:66562500 RuntimeKernel100ns:66562500}
--- PASS: TestStatsTime2 (0.02s)
PASS

[jterry75]

I like the idea. Can we not just query the working set size associated to the JO handle for the container in one pass? It seems like that should be a feature if it isnt already :)

[dcantah]

I like the idea. Can we not just query the working set size associated to the JO handle for the container in one pass? It seems like that should be a feature if it isnt already :)

At least not that I could find, I've asked some peeps to look around if there's something hidden..

[dcantah]

@kevpar ptal when you get a chance

[dcantah]

@kevpar Let me know if the latest update looks good here

[kevpar]

I think these changes go beyond "optimizing". For clarify, we should phrase the commit differently so the impact is clear. I'd suggest something like "wcow-process: Query stats directly from shim".

[dcantah]

I think these changes go beyond "optimizing". For clarify, we should phrase the commit differently so the impact is clear. I'd suggest something like "wcow-process: Query stats directly from shim".

@kevpar I can change the squashed commit msg on check-in to be more clear here

[kevpar]

I think these changes go beyond "optimizing". For clarify, we should phrase the commit differently so the impact is clear. I'd suggest something like "wcow-process: Query stats directly from shim".

@kevpar I can change the squashed commit msg on check-in to be more clear here

Can we change the PR title to? I think that's included in the squash commit title.

[msscotb]

lgtm

[dcantah]

@kevpar Ok, hopefully the last rendition of this :)

[kevpar]

LGTM