windows_exporter/internal/collector/memory/AGENTS.md

memory collector

The collector reads the single-instance PDH object Memory with pdh.CounterTypeRaw. The object exists on every Windows host, so no role is needed. It also calls GlobalMemoryStatusEx for the physical and virtual totals, which do not come from PDH. These notes were recorded on Windows Server 2025 (build 26100).

• Every PERF_COUNTER_LARGE_RAWCOUNT counter of this object is a gauge in bytes, except Available KBytes and Available MBytes. Cache Bytes Peak is the highest cache size since boot. In the sample, Available Bytes equals Available KBytes times 1024, and Available MBytes is the truncated value.
• Available Bytes equals the sum of Free & Zero Page List Bytes and the three Standby Cache ... Bytes counters (exact in the sample). Cache Bytes and System Cache Resident Bytes are the same value; the help text says they are equivalent.
• Every /sec counter is PERF_COUNTER_COUNTER; its raw value is a count since boot. Pages/sec equals Pages Input/sec plus Pages Output/sec (exact in the sample) and counts pages. Page Reads/sec and Page Writes/sec count disk operations, regardless of how many pages each operation moved.
• Long-Term Average Standby Cache Lifetime (s) is a gauge in seconds.
• Pool Paged Allocs and Pool Nonpaged Allocs are PERF_COUNTER_RAWCOUNT. The help text calls them the number of allocation calls; both were 0 on this host, so their behavior could not be checked.
• System Code Total Bytes (8192) was smaller than System Code Resident Bytes in the sample, although the help text calls the resident value a component of the total. Standby Cache Core Bytes was 0.

Counter reference

Recorded on Windows Server 2025 (build 26100). Raw and Base are the first and second values that pdh.CounterTypeRaw returns for the sample instance.

Memory

Single-instance.

Counters the collector reads:

Counter	Type	Raw	Base
Available Bytes	PERF_COUNTER_LARGE_RAWCOUNT	6625095680
Available KBytes	PERF_COUNTER_LARGE_RAWCOUNT	6469820
Available MBytes	PERF_COUNTER_LARGE_RAWCOUNT	6318
Cache Bytes	PERF_COUNTER_LARGE_RAWCOUNT	401428480
Cache Bytes Peak	PERF_COUNTER_LARGE_RAWCOUNT	558510080
Cache Faults/sec	PERF_COUNTER_COUNTER	13400536
Commit Limit	PERF_COUNTER_LARGE_RAWCOUNT	19728846848
Committed Bytes	PERF_COUNTER_LARGE_RAWCOUNT	11770671104
Demand Zero Faults/sec	PERF_COUNTER_COUNTER	49162751
Free & Zero Page List Bytes	PERF_COUNTER_LARGE_RAWCOUNT	602169344
Long-Term Average Standby Cache Lifetime (s)	PERF_COUNTER_RAWCOUNT	547
Modified Page List Bytes	PERF_COUNTER_LARGE_RAWCOUNT	23617536
Page Faults/sec	PERF_COUNTER_COUNTER	130811351
Page Reads/sec	PERF_COUNTER_COUNTER	1012866
Page Writes/sec	PERF_COUNTER_COUNTER	8667
Pages Input/sec	PERF_COUNTER_COUNTER	8156926
Pages Output/sec	PERF_COUNTER_COUNTER	244196
Pages/sec	PERF_COUNTER_COUNTER	8401122
Pool Nonpaged Allocs	PERF_COUNTER_RAWCOUNT	0
Pool Nonpaged Bytes	PERF_COUNTER_LARGE_RAWCOUNT	523558912
Pool Paged Allocs	PERF_COUNTER_RAWCOUNT	0
Pool Paged Bytes	PERF_COUNTER_LARGE_RAWCOUNT	697995264
Pool Paged Resident Bytes	PERF_COUNTER_LARGE_RAWCOUNT	673656832
Standby Cache Core Bytes	PERF_COUNTER_LARGE_RAWCOUNT	0
Standby Cache Normal Priority Bytes	PERF_COUNTER_LARGE_RAWCOUNT	5178191872
Standby Cache Reserve Bytes	PERF_COUNTER_LARGE_RAWCOUNT	844734464
System Cache Resident Bytes	PERF_COUNTER_LARGE_RAWCOUNT	401428480
System Code Resident Bytes	PERF_COUNTER_LARGE_RAWCOUNT	11939840
System Code Total Bytes	PERF_COUNTER_LARGE_RAWCOUNT	8192
System Driver Resident Bytes	PERF_COUNTER_LARGE_RAWCOUNT	60264448
System Driver Total Bytes	PERF_COUNTER_LARGE_RAWCOUNT	27291648
Transition Faults/sec	PERF_COUNTER_COUNTER	63418925
Transition Pages RePurposed/sec	PERF_COUNTER_COUNTER	10022193
Write Copies/sec	PERF_COUNTER_COUNTER	1722840

Not read by the collector:

• PERF_COUNTER_RAWCOUNT: Free System Page Table Entries
• PERF_RAW_FRACTION: % Committed Bytes In Use