Linux Profiling on MID
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Linux Profiling on MID
Profiling Tools
oprofile
Oprofile is a tool for system wide profiling. It can list both processes and modules, as well as the kernel itself, and also supports gathering performance monitor events from IA chipsets (the latest they have is Pentium M, so we still need to add the new Silverthorne events). To run it, Enable CONFIG_PROFILING=y and CONFIG_OPROFILE=m in the kernel config (as well as debug info if possible), copy the vmlinux uncompressed kernel to /boot on the target, and install oprofile. This can be done with yum install oprofile on FC6 systems. The developer site is at http://oprofile.sourceforge.net)
strace
Strace traces through syscalls, each of which trigger an interrupt and a switch to and from kernel space, thus they take alot of time and should be reduced if possible. It can be installed via yum install strace on FC6 machines.
Statmonitor
System monitoring utility, written in plain C. Allows application execution and performance monitoring, saving results into XML files. Monitors CPU, memory, network and disk usage on a per-application or per-system basis. (http://sourceforge.net/projects/statmonitor)
VTune
VTune is an advanced user side debug and profiler tool which can break down execution and trace by library, file, function, etc. It is designed to help optimize applications. (http://www3.intel.com/cd/software/products/asmo-na/eng/239145.htm).
Systemtap
SystemTap provides a simple command line interface and scripting language for writing instrumentation for a live running kernel. We are publishing samples, as well as enlarging the internal "tapset" script library to aid reuse and abstraction. We also plan to support probing userspace applications. We are investigating interfacing Systemtap with similar tools such as Frysk, Oprofile and LTT. (http://sourceware.org/systemtap/)
/Proc Filesystem
| Processor Function | Tools Using It | Data Provided |
|---|---|---|
| /proc/stat | statmonitor, appr, bltk | user, niced, and system processes executed per cpu since boot idle, iowait, irq service, and softirq service time since boot (in ticks) interrupt counts for each irq type since boot context switch count since boot seconds since boot processes currently running and those currently blocked due to iowait |
| /proc/diskstats | statmonitor, appr, bltk | For each mounted image: number of reads issued number of reads merged number of writes merged number of sectors read number of milliseconds spent reading [[BR]number of writes completed number of sectors written number of milliseconds spent writing number of I/Os currently in progress number of milliseconds spent doing I/Os weighted number of milliseconds spent doing I/Os |
| /proc/cmdline | bltk | The command line parameters passed to vmlinuz during boot |
| /proc/config.gz | bltk | Contains a gzipped copy of the config file used to build the kernel |
| /proc/cpuinfo | bltk | processor, vendor_id, cpu family, model, model name, stepping, cpu MHz, cache size |
| /proc/interrupts | bltk | Interrupt list with counts since boot, for example: timer, i8042, rtc, acpi, i8042, ide0, uhci_hcd:usb3, ehci_hcd:usb1, uhci_hcd:usb2, uhci_hcd:usb4, uhci_hcd:usb5, sdhci:slot0, HDA Intel |
| /proc/meminfo | bltk | Virtual and physical memory page counts |
| /proc/modules | bltk | List of active modules (accessed by lsmod) |
| /proc/partitions | bltk | List of actively mounted hard disks |
| /proc/swaps | bltk | List of actively mounted swap partitions |
| /proc/version | bltk | Shows the kernel version and its build info (accessed by uname -a) |
| /proc/vmstat | bltk | virtual and physical memory page stats |
| /proc/net/dev | statmonitor, appr | information about the configured network interfaces Used by network administrators to view the status of the network |
| /proc/<pid>/stat | statmonitor, appr | Process statistics including execution time, sleep time, memory stats, and interrupt stats (accessed by ps) |
| /proc/<pid>/status | strace, appr | Same info as /proc/<pid>/stat but in readable form |
| /proc/<pid>/ctl | strace, appr | A write-only file to which structured messages are written directing the system to change some aspect of the process's state or control its behavior in some way. These can include PCSTOP, PCRUN, PCSTRACE, PCSKILL, PCSHOLD , etc. |
| /proc/<pid>/as | strace, appr | Used to read and/or write from/to the process's address space |
| /proc/<pid>/mem | strace, appr | Description of the memory map held by the process |
| /proc/<pid>/regs | strace, appr | Lists various CPU registers such as the frame and stack pointers These are dumped when a fault occurs |
| /proc/acpi/alarm | bltk | Interface to the Real Time Clock (RTC). It is written to schedule an alarm that will generate a hardware wake event when in the sleeping state. Reading it shows the currently set alarm time |
| /proc/acpi/ac_adapter | bltk | A directory which contains state files for each detectable AC adapter. The adapter name corresponds to its entry in the BIOS's DSDT file The state file shows whether it is attached or not (i.e. whether the platform is running on battery or not) |
| /proc/acpi/battery | bltk | A directory which contains state, info, and alarm files for each detectable Battery. The battery name corresponds to its entry in the BIOS's DSDT file The state file shows the battery's connection status, capacity, charging status, charging rate, it's remaining capacity, and it's current voltage. The info file gives the battery's design specifications and model info The alarm file shows the status of the battery's low power alarm (if available) |
| /proc/acpi/processor | bltk | This is the interface to each processor's voltage and frequency scaling controls. |
Kernel Command Line Arguments
| Parameter | Config Dependencies | Description |
|---|---|---|
| acpi_dbg_layer=<int> | CONFIG_ACPI | Each bit of the <int> indicates an ACPI debug layer, 1: enable, 0: disable. It is useful for boot time debugging. After system has booted up, it can be set via /proc/acpi/debug_layer. |
| acpi_dbg_level=<int> | CONFIG_ACPI | Each bit of the <int> indicates an ACPI debug level, 1: enable, 0: disable. It is useful for boot time debugging. After system has booted up, it can be set via /proc/acpi/debug_level. |
| profile | Enable kernel profiling via /proc/profile Format: [schedule,]<number> Param: "schedule" - profile schedule points. Param: <number> - step/bucket size as a power of 2 for statistical time based profiling. Param: "sleep" - profile D-state sleeping (millisecs) | |
| prof=sleep | CONFIG_PROFILING | causes the kernel to profile the amount of time spent in uninterruptible sleeps. |
Hardware Performance Monitor Events
http://oprofile.sourceforge.net/docs/intel-p6-mobile-events.php3