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linux_wiki:high_system_load [2015/12/08 08:58] billdozor [Traffic/Bridge analogy] |
linux_wiki:high_system_load [2016/03/14 11:32] billdozor |
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| * 2 CPU/Cores = 100% is load 2.00 | * 2 CPU/Cores = 100% is load 2.00 | ||
| * 4 CPU/Cores = 100% is load 4.00 | * 4 CPU/Cores = 100% is load 4.00 | ||
| - | * Example: From the analogy above, each CPU Core can handle | + | * Example: From the analogy above, each CPU Core can actively process |
| ===== Calculate Overall CPU Load ===== | ===== Calculate Overall CPU Load ===== | ||
| - | * Get number of CPUs | + | * Get number of CPUs< |
| - | * <code bash> | + | OR |
| + | nproc</ | ||
| * Load Average / NumProccessors = decimal % load | * Load Average / NumProccessors = decimal % load | ||
| * Example: LoadAvg(1.5) / 2 Processors = 0.75 or 75% system load on a dual core system. | * Example: LoadAvg(1.5) / 2 Processors = 0.75 or 75% system load on a dual core system. | ||
| Line 92: | Line 93: | ||
| ---- | ---- | ||
| - | ==== High CPU ==== | + | ===== High CPU ===== |
| Clues that you should investigate high CPU usage: | Clues that you should investigate high CPU usage: | ||
| Line 109: | Line 110: | ||
| ---- | ---- | ||
| - | ==== High Memory Use ==== | + | ===== High Memory Use ===== |
| Notes on Linux memory management | Notes on Linux memory management | ||
| Line 136: | Line 137: | ||
| ---- | ---- | ||
| - | ==== Disk I/O ==== | + | ===== Disk I/O ===== |
| * I/O wait (wa) is the percentage of time a CPU is waiting on disk. | * I/O wait (wa) is the percentage of time a CPU is waiting on disk. | ||
| Line 148: | Line 149: | ||
| * High CPU " | * High CPU " | ||
| + | \\ | ||
| **iostat** - View I/O stats with extended statistics, every 3 seconds | **iostat** - View I/O stats with extended statistics, every 3 seconds | ||
| <code bash> | <code bash> | ||
| Line 154: | Line 156: | ||
| * " | * " | ||
| + | \\ | ||
| **iotop** - Live disk I/O similar to top | **iotop** - Live disk I/O similar to top | ||
| <code bash> | <code bash> | ||
| Line 159: | Line 162: | ||
| </ | </ | ||
| + | \\ | ||
| **lsof** - If a particular device is discovered, another option for further details is to list open files for that mount point. | **lsof** - If a particular device is discovered, another option for further details is to list open files for that mount point. | ||
| * Device discovered via iostat | * Device discovered via iostat | ||