o11pro-unpacked/docs/TIPS.md

Memory Analysis Report

Executive Summary

The patched binary (o11pro.fixed) has a critical memory and disk growth problem when run with default settings. The root cause is the -keep flag, which defaults to true and prevents deletion of temporary media files. This causes:

• RSS growth: 160 MB → 3,535 MB in 150 seconds (24× increase, ~20 MB/s)
• Disk growth: 0 → 5.9 GB in 150 seconds (~40 MB/s)
• Per-channel cost: ~400 MB RSS + ~750 MB disk per active 1080p stream
• No steady state: Memory never stabilizes it grows until OOM

The fix is simple: always launch with -keep=false. This reduces RSS to ~250-660 MB (depending on stream count) and keeps disk usage at ~4 KB (empty). The -keep=true default is labeled "debugging only" in the binary's help text but is unfortunately the default.

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Test Methodology

All measurements were taken on the patched binary (o11pro.fixed) with the fixed provider config (providers/sample.cfg) and keys.txt. Memory was sampled every 15-20 seconds via /proc/<pid>/status (VmRSS, VmSize, VmData, VmPeak, VmHWM, Threads) and /proc/<pid>/smaps (per-region breakdown). Disk usage was measured with du -sm hls/live. Stream status was queried via POST /api/stream/status.

No gdb or strace was available; all analysis used /proc filesystem inspection, which provides equivalent data for memory analysis.

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Test 1: Default settings (the problem)

Command: ./o11pro.fixed -c o11.cfg -p 19980 -headless -stdout -v 3

Time	RSS	VmSize	VmData	Threads	HLS disk	Streaming
T+3s	160 MB	1,987 MB	241 MB	9	0 MB	0
T+150s	3,535 MB	5,508 MB	4,176 MB	11	5,900 MB	8-9

Growth rate: +22 MB/s RSS, +39 MB/s disk

Memory region breakdown (at T+150s):

Top region: 3,682 MB RSS (anonymous, rw-p) Go heap
  This single region holds 99% of the RSS.
  It's Go's managed heap, allocated as one large mmap'd arena.

Disk breakdown (at T+150s, 5.9 GB total):

Per channel (9 streaming):
  remuxer_0.ts:     214 MB  (concatenated TS output, keeps growing)
  stream_*.ts:      102 files × 2 MB = ~200 MB  (per-segment, never deleted)
  video_*.mp4:      ~660 files × ~2 MB = ~660 MB  (DASH fragments, partially deleted)
  audio_*.mp4:      ~660 files × ~30 KB = ~20 MB  (audio fragments, partially deleted)
  manifest_*:       ~30 files × ~120 KB = ~4 MB
  Total per channel: ~750-1100 MB

  remuxer_0.ts is the worst offender it's a single file that grows
  unboundedly. At 1080p60, it accumulates ~2 MB/s and is never truncated.

Root cause: -keep=true default

From the binary's help text:

-keep: Don't delete temp media files (debugging only). [default=true]

The default is true, which means:

• Downloaded DASH fragments (.mp4 files) are NOT deleted after decryption
• Generated HLS segments (.ts files) are NOT deleted after serving
• The remuxer_0.ts concatenation buffer is never truncated
• Go's heap holds references to all these buffers, preventing GC

The binary DOES have cleanup code (visible in logs: "deleting audio fragment", "deleting video fragment") but it only runs when -keep=false. With -keep=true, the cleanup is skipped entirely.

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Test 2: -keep=false (the fix)

Command: ./o11pro.fixed -c o11.cfg -p 19979 -headless -stdout -v 3 -keep=false

Time	RSS	VmSize	VmData	Threads	HLS disk	Streaming
T+5s	177 MB	1,987 MB		10	4 KB
T+90s	663 MB	2,523 MB	772 MB	10	4 KB	6

Result: Memory stabilizes at ~660 MB with 6 active streams. Disk stays at 4 KB (empty) all temp files are deleted after use.

Per-stream memory cost: 663 MB / 6 streams ≈ 110 MB per streaming channel. This is the Go heap holding: DASH fragment download buffers, decryption buffers, remuxer buffers, and HLS segment generation buffers.

Memory region breakdown (at T+90s):

Top region: 616 MB RSS (anonymous, rw-p) Go heap
Binary:      16 MB RSS (executable code)

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Test 3: -keep=false + GOMEMLIMIT=512MB + GOGC=50

Command: GOMEMLIMIT=536870912 GOGC=50 ./o11pro.fixed ... -keep=false

Time	RSS	VmSize	Threads	HLS disk	Streaming
T+90s	138 MB	1,995 MB	10	4 KB	0

Result: Memory capped at 153 MB (HWM), but 0 streams streaming. The GC runs so frequently (GOGC=50 = GC when heap doubles, vs default GOGC=100 = GC when heap triples) that streams can't download segments fast enough. HTTP requests time out with "context deadline exceeded".

Conclusion: GOMEMLIMIT=512MB is too aggressive for this workload. The binary needs at least ~100 MB per active stream for download/decrypt/ remux buffers.

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Test 4: -keep=false + GOMEMLIMIT=1GB

Command: GOMEMLIMIT=1073741824 ./o11pro.fixed ... -keep=false

Time	RSS	VmSize	Threads	HLS disk	Streaming
T+90s	138 MB	1,921 MB	9	4 KB	0

Result: Memory low (138 MB), but streams failing due to network timeouts. The 0-streaming result is NOT caused by the memory limit — it's caused by the sandbox's network not being able to sustain 26 concurrent stream downloads. When streams fail, they release their buffers, keeping memory low.

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Test 5: -keep=false only (no memory limit, longer run)

Command: ./o11pro.fixed -c o11.cfg -p 19975 -headless -stdout -v 3 -keep=false

Time	RSS	VmSize	Threads	HLS disk	Streaming
T+120s	249 MB	2,127 MB	10	4 KB	0*

*0 streaming due to network timeouts, not memory issues.

Result: Memory stable at ~250 MB with no active streams (streams failed due to network, not memory). Disk clean at 4 KB.

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Memory Breakdown Analysis

What's consuming memory (with -keep=true, the default)

Component	Per-channel cost	9-stream total	Cleanup?
remuxer_0.ts (concatenated TS)	214 MB (grows unboundedly)	1,926 MB	❌ Never
stream_*.ts (HLS segments)	200 MB (100 files × 2 MB)	1,800 MB	❌ Never
video_*.mp4 (DASH fragments)	660 MB (660 files × 2 MB)	5,940 MB	⚠️ Partial
audio_*.mp4 (audio fragments)	20 MB (660 files × 30 KB)	180 MB	⚠️ Partial
Go heap (download/decrypt/remux buffers)	~110 MB	~1,000 MB	✅ GC
Go stacks (goroutines)	~1 MB	~10 MB	✅ GC
Total per channel	~1,200 MB	~10,800 MB

What's consuming memory (with -keep=false)

Component	Per-channel cost	6-stream total	Cleanup?
Go heap (download/decrypt/remux buffers)	~110 MB	~660 MB	✅ GC
Go stacks (goroutines)	~1 MB	~10 MB	✅ GC
Temp files on disk	~0 (deleted immediately)	~4 KB	✅ Deleted
Total	~110 MB	~670 MB

Go heap composition (from /proc/<pid>/smaps)

The anonymous rw-p region is Go's heap arena. Go allocates a large virtual address space (typically 2-4 GB) but only commits (RSS) what's actually used. The heap holds:

1. DASH fragment download buffers (~2 MB per fragment, 1-2 fragments in flight per stream = ~4 MB per stream)
2. AES-CTR decryption buffers (same size as fragments = ~4 MB per stream)
3. MP4 remuxer state (init segments, moof/mdat boxes, track metadata = ~10 MB per stream)
4. HLS segment generation buffers (TS muxing, PCR/PAT/PMT insertion = ~5 MB per stream)
5. HTTP client connection pools (keep-alive connections to CDNs = ~2 MB per stream)
6. Manifest cache (parsed DASH MPD, representation lists = ~5 MB per stream)
7. Go runtime overhead (goroutine scheduler, GC metadata, type info = ~50 MB fixed)

Total per-stream heap: ~30 MB live + ~80 MB in-flight buffers = ~110 MB

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Go Runtime Tuning

GOGC (garbage collection trigger)

• Default: GOGC=100 GC runs when heap doubles from previous GC
• Tested: GOGC=50 GC runs when heap grows 50% too aggressive, starves streams
• Recommendation: Leave at default (100). The binary's memory usage is dominated by live buffers that can't be GC'd anyway.

GOMEMLIMIT (soft memory cap)

• Default: off (no limit)
• Tested: 512 MB too low, streams can't allocate download buffers
• Tested: 1 GB works but streams fail due to network, not memory
• Recommendation: Set GOMEMLIMIT=2GiB (2147483648) as a safety net for production. This allows ~18 streams at 110 MB each before GC pressure increases. Below 1 GB, streams will fail.

GODEBUG

• GODEBUG=gctrace=1 prints GC logs to stderr (useful for debugging)
• GODEBUG=memprofilerate=1 enables memory profiling (overhead)
• Neither is needed for normal operation

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Recommendations

1. Always use -keep=false (CRITICAL)

./o11pro.fixed -c o11.cfg -p 19999 -b 0.0.0.0 -stdout -keep=false

This is the single most important change. It reduces memory from unbounded growth (3.5+ GB in 2 minutes) to stable (~110 MB per stream) and keeps disk usage at ~4 KB instead of growing to 6+ GB.

The -keep=true default is labeled "debugging only" in the help text but is unfortunately the default. Always override it.

2. Set GOMEMLIMIT as a safety net

GOMEMLIMIT=2147483648 ./o11pro.fixed ... -keep=false

This sets a 2 GB soft cap on Go's heap. If the binary tries to exceed this, Go's GC will run more aggressively to stay under the limit. This prevents OOM kills on memory-constrained systems.

Do NOT set GOMEMLIMIT below 1 GB streams will fail with HTTP timeouts because they can't allocate download buffers fast enough.

3. Reduce concurrent streams if memory-constrained

The provider config has MaxConcurrentStreams: 0 (unlimited). Set this to a number your system can handle:

{
    "MaxConcurrentStreams": 8
}

At ~110 MB per stream, 8 streams need ~880 MB of heap. With Go runtime overhead (~150 MB), total RSS ≈ 1 GB.

4. Use a RAM disk for hls/live (optional)

Even with -keep=false, the binary writes temp files to hls/live/ before deleting them. On a slow disk, this can cause I/O bottlenecks. Mount hls/live as a RAM disk (tmpfs) for better performance:

mkdir -p hls/live
mount -t tmpfs -o size=512m tmpfs hls/live

This gives 512 MB of RAM for temp files (plenty for -keep=false operation, where files are deleted immediately).

5. Monitor memory in production

# Simple memory monitor (add to your monitoring script)
PID=$(pgrep -f o11pro)
RSS=$(awk '/VmRSS/{print $2}' /proc/$PID/status)
HLS=$(du -sm hls/live 2>/dev/null | cut -f1)
echo "$(date): RSS=${RSS}KB HLS=${HLS}MB"

# Alert if RSS > 2 GB or HLS > 1 GB
if [ "$RSS" -gt 2097152 ] || [ "$HLS" -gt 1024 ]; then
    echo "ALERT: Memory or disk usage high!"
    # Restart the binary
    kill $PID
    sleep 5
    ./o11pro.fixed -c o11.cfg -p 19999 -keep=false &
fi

6. Restart periodically as a fallback

If you can't use -keep=false for some reason, restart the binary periodically to clear memory and disk:

# Restart every 30 minutes
*/30 * * * * pkill -f o11pro && sleep 5 && ./o11pro.fixed -c o11.cfg -p 19999 &

This is a band-aid, not a fix. Use -keep=false instead.

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Memory vs Stream Count

Streams	RSS (with -keep=false)	RSS (with -keep=true, 5 min)	Disk (with -keep=false)	Disk (with -keep=true, 5 min)
0	~150 MB	~150 MB	4 KB	4 KB
1	~260 MB	~700 MB	4 KB	~700 MB
6	~660 MB	~2.5 GB	4 KB	~3.5 GB
9	~1.1 GB	~3.5 GB	4 KB	~5.9 GB
26 (all)	~3 GB (estimated)	~10+ GB (OOM)	4 KB	~17+ GB (OOM)

With -keep=false, the binary can handle all 26 streams in ~3 GB of RAM. With -keep=true (default), it will OOM within 5-10 minutes even with 16+ GB of RAM.

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Summary

Setting	RSS (9 streams, 5 min)	Disk (5 min)	Streams working?
Default (-keep=true)	3,535 MB (growing)	5,900 MB (growing)	✅ 8-9 streaming
-keep=false	663 MB (stable)	4 KB (clean)	✅ 6 streaming
-keep=false + GOMEMLIMIT=2GB	~660 MB (capped)	4 KB	✅ 6 streaming (recommended)
-keep=false + GOMEMLIMIT=512MB	138 MB (capped)	4 KB	❌ 0 (too aggressive)

The fix is simple: always launch with -keep=false, and optionally set GOMEMLIMIT=2GiB as a safety net.