[2.5.35] Run Queue Statistics
RFC PATCH 1/1 [2.5.35] Run Queue Statistics
This patch adds two counters, runque and runocc, similar to those in traditional UNIX systems, to measure the run queue occupancy. Every second, 'runque' is incremented by the run queue size, and 'runocc' is incremented by one if the run queue is not empty.
I am not comfortable about putting the calculation in the same function as the load average calculation, but I didn't want to call count_active_tasks() twice. Comments are welcome.
Lev
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diff -urN linux-2.5.35.orig/fs/proc/proc_misc.clinux-2.5.35/fs/proc/proc_misc.c
fs/proc/proc_misc.c +5 -2
@@ -386,7 +386,8 @@"allocstall %u\n" "ctxt %lu\n" "btime %lu\n" -"processes %lu\n" , +"processes %lu\n" +"runque %u %u\n" , kstat.pgalloc, kstat.pgfree, kstat.pgactivate,
@@ -399,7 +400,9 @@ kstat.allocstall,nr_context_switches (), xtime.tv_sec - jif /HZ , - total_forks); + total_forks, + kstat.runque, + kstat.runocc);return proc_calc_metrics (page, start, off, count, eof, len); }
diff -urN linux-2.5.35.orig/include/linux/kernel_stat.h linux-2.5.35/include/linux/kernel_stat.h
include/linux/kernel_stat.h +1 -0
@@ -31,6 +31,7 @@unsigned int pgfault, pgmajfault;unsigned int pgscan, pgsteal;unsigned int pageoutrun, allocstall; +unsigned int runque, runocc;#if !defined(CONFIG_ARCH_S390 )unsigned int irqs[NR_CPUS ][NR_IRQS ];#endif
kernel/timer.c +23 -10
@@ -592,11 +592,11 @@ }/* -* Nr of active tasks - counted in fixed-point numbers +* Nr of active tasks */ static unsigned long count_active_tasks (void ) { -return (nr_running () +nr_uninterruptible ()) *FIXED_1 ; +return nr_running () +nr_uninterruptible (); }/*
@@ -615,16 +615,29 @@*/ static inline void calc_load (unsigned long ticks) { -unsigned long active_tasks;/* fixed-point */ -static int count =LOAD_FREQ ; +unsigned long active_tasks; +unsigned long fp_active_tasks;/* fixed-point */ +static int load_count =LOAD_FREQ ; +static int runq_count =HZ ; - count -= ticks; -if (count <0 ) { - count +=LOAD_FREQ ; + load_count -= ticks; + runq_count -= ticks; +if (load_count <0 || runq_count <0 ) { active_tasks =count_active_tasks (); -CALC_LOAD (avenrun[0 ],EXP_1 , active_tasks); -CALC_LOAD (avenrun[1 ],EXP_5 , active_tasks); -CALC_LOAD (avenrun[2 ],EXP_15 , active_tasks); +if (runq_count <0 ) { + runq_count +=HZ ; +if (active_tasks) { + kstat.runque += active_tasks; + kstat.runocc ++; + } + } +if (load_count <0 ) { + load_count +=LOAD_FREQ ; + fp_active_tasks = active_tasks *FIXED_1 ; +CALC_LOAD (avenrun[0 ],EXP_1 , fp_active_tasks); +CALC_LOAD (avenrun[1 ],EXP_5 , fp_active_tasks); +CALC_LOAD (avenrun[2 ],EXP_15 , fp_active_tasks); + } } }
Hi,
Quoted 8 lines
This patch adds two counters, runque and runocc, similar to those in traditional UNIX systems, to measure the run queue occupancy. Every second, 'runque' is incremented by the run queue size, and 'runocc' is incremented by one if the run queue is not empty.
I am not comfortable about putting the calculation in the same function as the load average calculation, but I didn't want to call
count_active_tasks()twice. Comments are welcome.
On a semi related note, vmstat wants to know the number of running, blocked and swapped processes. strace vmstat one day and you will see it currently opens /proc/*/stat (ie one open for each process) just to get these stats. Yet another place where the monitoring utilities disturb the system way too much.
Can we get some things in /proc/stat to give us these numbers? Does "swapped" make any sense on Linux?
Anton
Quoted 8 lines · Anton Blanchard
On a semi related note, vmstat wants to know the number of running, blocked and swapped processes. strace vmstat one day and you will see it currently opens
/proc/*/stat(ie one open for each process) just to get these stats. Yet another place where the monitoring utilities disturb the system way too much.Can we get some things in
/proc/statto give us these numbers? Does "swapped" make any sense on Linux?
Runnable can be done currently, blocked on IO is trivial once Andrew has pushed the iowait stats to Linus.
Swapped doesn't make any sense at the moment, but it should. A system without load control is just too vulnerable to sudden load spikes. If Andrew has interest I'll pick up the work I did in that area ...
I'll also update vmstat to just use /proc/stat instead of looking at all /proc/*/stat files.
cheers,
Rik
Signature · 5 lines
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Quoted 18 lines · Rik van Riel
Quoted 8 lines · Anton Blanchard
On a semi related note, vmstat wants to know the number of running, blocked and swapped processes. strace vmstat one day and you will see it currently opens
/proc/*/stat(ie one open for each process) just to get these stats. Yet another place where the monitoring utilities disturb the system way too much.Can we get some things in
/proc/statto give us these numbers? Does "swapped" make any sense on Linux?Runnable can be done currently, blocked on IO is trivial once Andrew has pushed the iowait stats to Linus.
Swapped doesn't make any sense at the moment, but it should. A system without load control is just too vulnerable to sudden load spikes. If Andrew has interest I'll pick up the work I did in that area ...
Quoted 6 lines
I'll also update vmstat to just use
/proc/statinstead of looking at all/proc/*/statfiles.cheers,
Rik
Amusingly, the number of running processes can be found in /proc/loadavg, of all places, right now.
Quoted 11 lines · Rik van Riel
Quoted 8 lines · Anton Blanchard
On a semi related note, vmstat wants to know the number of running, blocked and swapped processes. strace vmstat one day and you will see it currently opens
/proc/*/stat(ie one open for each process) just to get these stats. Yet another place where the monitoring utilities disturb the system way too much.Can we get some things in
/proc/statto give us these numbers? Does "swapped" make any sense on Linux?
Certainly sounds good. Opening every /proc/<pid>/stat is gross.
Quoted 3 lines
Runnable can be done currently, blocked on IO is trivial once Andrew has pushed the iowait stats to Linus.
That'll be a while off yet. I'd like to make sure that we have all the externally visible changes stable for a week or so, /proc/diskstats settled down, userspace updated and tested etc.
Just to minimise the disruption and churn which these changes will cause.