Re: [patch] Latency Tracer, voluntary-preempt-2.6.8-rc4-O6

[Lee Revell]

On Thu, 2004-08-12 at 19:51, Ingo Molnar wrote:
> i've uploaded the latest version of the voluntary-preempt patch:
>      
>   http://redhat.com/~mingo/voluntary-preempt/voluntary-preempt-2.6.8-rc4-O6
> 

Interesting results.  One of the problems is kallsyms_lookup, triggered
by the printks:

 0.100ms (+0.000ms): emit_log_char (printk)
 0.100ms (+0.000ms): emit_log_char (printk)
 0.101ms (+0.000ms): emit_log_char (printk)
 0.101ms (+0.000ms): preempt_schedule (printk)
 0.101ms (+0.000ms): release_console_sem (printk)
 0.102ms (+0.000ms): preempt_schedule (release_console_sem)
 0.102ms (+0.000ms): call_console_drivers (release_console_sem)
 0.103ms (+0.000ms): _call_console_drivers (call_console_drivers)
 0.103ms (+0.000ms): __call_console_drivers (call_console_drivers)
 0.105ms (+0.001ms): vt_console_print (__call_console_drivers)
 0.106ms (+0.001ms): vc_cons_allocated (vt_console_print)
 0.108ms (+0.001ms): preempt_schedule (release_console_sem)
 0.108ms (+0.000ms): __print_symbol (print_context_stack)
 0.109ms (+0.001ms): kallsyms_lookup (__print_symbol)
 0.491ms (+0.381ms): sprintf (__print_symbol)
 0.492ms (+0.000ms): vsprintf (sprintf)
 0.492ms (+0.000ms): vsnprintf (vsprintf)
 0.494ms (+0.001ms): number (vsnprintf)
 0.496ms (+0.001ms): number (vsnprintf)
 0.497ms (+0.001ms): printk (__print_symbol)
 0.497ms (+0.000ms): vscnprintf (printk)
 0.497ms (+0.000ms): vsnprintf (vscnprintf)
 0.499ms (+0.001ms): emit_log_char (printk)
 0.499ms (+0.000ms): emit_log_char (printk)

 0.778ms (+0.000ms): emit_log_char (printk)
 0.779ms (+0.000ms): emit_log_char (printk)
 0.779ms (+0.000ms): preempt_schedule (printk)
 0.779ms (+0.000ms): release_console_sem (printk)
 0.780ms (+0.000ms): preempt_schedule (release_console_sem)
 0.780ms (+0.000ms): call_console_drivers (release_console_sem)
 0.781ms (+0.000ms): _call_console_drivers (call_console_drivers)
 0.781ms (+0.000ms): __call_console_drivers (call_console_drivers)
 0.781ms (+0.000ms): vt_console_print (__call_console_drivers)
 0.782ms (+0.000ms): vc_cons_allocated (vt_console_print)
 0.782ms (+0.000ms): preempt_schedule (release_console_sem)
 0.782ms (+0.000ms): __print_symbol (print_context_stack)
 0.783ms (+0.000ms): kallsyms_lookup (__print_symbol)
 1.448ms (+0.665ms): sprintf (__print_symbol)
 1.448ms (+0.000ms): vsprintf (sprintf)
 1.448ms (+0.000ms): vsnprintf (vsprintf)
 1.450ms (+0.001ms): number (vsnprintf)
 1.452ms (+0.001ms): number (vsnprintf)
 1.453ms (+0.000ms): printk (__print_symbol)
 1.453ms (+0.000ms): vscnprintf (printk)
 1.453ms (+0.000ms): vsnprintf (vscnprintf)
 1.455ms (+0.001ms): emit_log_char (printk)
 1.456ms (+0.000ms): emit_log_char (printk)

Lee



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