forked from wrenn/wrenn
pptx704
1178ab8b21
Three issues fixed: 1. Memory metrics read host-side VmRSS of the Firecracker process, which includes guest page cache and never decreases. Replaced readMemRSS(fcPID) with readEnvdMemUsed(client) that queries envd's /metrics endpoint for guest-side total - MemAvailable. This matches neofetch and reflects actual process memory. 2. Added Firecracker balloon device (deflate_on_oom, 5s stats) and envd-side periodic page cache reclaimer (drop_caches when >80% used). Reclaimer is gated by snapshot_in_progress flag with sync() before freeze to prevent memory corruption during pause. 3. Sampling interval 500ms → 1s, ring buffer capacities adjusted to maintain same time windows. Reduces per-host HTTP load from 240 calls/sec to 120 calls/sec at 120 capsules. Also: maxDiffGenerations 8 → 1 (merge every re-pause since UFFD lazy-loads anyway), envd mem_used formula uses total - available.
90 lines
2.5 KiB
Go
90 lines
2.5 KiB
Go
package sandbox
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import (
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"encoding/json"
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"fmt"
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"io"
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"os"
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"strconv"
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"strings"
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"syscall"
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"git.omukk.dev/wrenn/wrenn/internal/envdclient"
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)
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// cpuStat holds raw CPU jiffies read from /proc/{pid}/stat.
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type cpuStat struct {
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utime uint64
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stime uint64
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}
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// readCPUStat reads user and system CPU jiffies from /proc/{pid}/stat.
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// Fields 14 (utime) and 15 (stime) are 1-indexed in the man page;
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// after splitting on space, they are at indices 13 and 14.
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func readCPUStat(pid int) (cpuStat, error) {
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path := fmt.Sprintf("/proc/%d/stat", pid)
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data, err := os.ReadFile(path)
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if err != nil {
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return cpuStat{}, fmt.Errorf("read stat: %w", err)
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}
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content := string(data)
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idx := strings.LastIndex(content, ")")
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if idx < 0 {
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return cpuStat{}, fmt.Errorf("malformed /proc/%d/stat: no closing paren", pid)
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}
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fields := strings.Fields(content[idx+2:])
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if len(fields) < 13 {
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return cpuStat{}, fmt.Errorf("malformed /proc/%d/stat: too few fields (%d)", pid, len(fields))
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}
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utime, err := strconv.ParseUint(fields[11], 10, 64)
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if err != nil {
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return cpuStat{}, fmt.Errorf("parse utime: %w", err)
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}
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stime, err := strconv.ParseUint(fields[12], 10, 64)
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if err != nil {
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return cpuStat{}, fmt.Errorf("parse stime: %w", err)
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}
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return cpuStat{utime: utime, stime: stime}, nil
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}
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// readEnvdMemUsed fetches mem_used from envd's /metrics endpoint. Returns
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// guest-side total - MemAvailable (actual process memory, excluding reclaimable
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// page cache). VmRSS of the Firecracker process includes guest page cache and
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// never decreases, so this is the accurate metric for dashboard display.
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func readEnvdMemUsed(client *envdclient.Client) (int64, error) {
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resp, err := client.HTTPClient().Get(client.BaseURL() + "/metrics")
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if err != nil {
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return 0, fmt.Errorf("fetch envd metrics: %w", err)
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}
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defer resp.Body.Close()
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if resp.StatusCode != 200 {
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return 0, fmt.Errorf("envd metrics: status %d", resp.StatusCode)
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}
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body, err := io.ReadAll(resp.Body)
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if err != nil {
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return 0, fmt.Errorf("read envd metrics body: %w", err)
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}
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var m struct {
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MemUsed int64 `json:"mem_used"`
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}
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if err := json.Unmarshal(body, &m); err != nil {
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return 0, fmt.Errorf("decode envd metrics: %w", err)
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}
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return m.MemUsed, nil
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}
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// readDiskAllocated returns the actual allocated bytes (not apparent size)
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// of the file at path. This uses stat's block count × 512.
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func readDiskAllocated(path string) (int64, error) {
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var stat syscall.Stat_t
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if err := syscall.Stat(path, &stat); err != nil {
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return 0, fmt.Errorf("stat %s: %w", path, err)
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}
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return stat.Blocks * 512, nil
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}
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