[RFC] shrink task_struct by removing per_cpu utime and stime

[RFC] shrink task_struct by removing per_cpu utime and stime

[William Lee Irwin III]

These statistics severely bloat the task_struct and nothing in
userspace can rely on them as they're conditional on CONFIG_SMP. If
anyone is using them (or just wants them around), please speak up.


Cheers,
Bill


===== fs/proc/array.c 1.24 vs edited =====
--- 1.24/fs/proc/array.c	Thu Jul  4 22:54:38 2002
+++ edited/fs/proc/array.c	Tue Jul 16 00:35:26 2002
@@ -685,25 +685,3 @@
 out:
 	return retval;
 }
-
-#ifdef CONFIG_SMP
-int proc_pid_cpu(struct task_struct *task, char * buffer)
-{
-	int i, len;
-
-	len = sprintf(buffer,
-		"cpu  %lu %lu\n",
-		jiffies_to_clock_t(task->utime),
-		jiffies_to_clock_t(task->stime));
-		
-	for (i = 0 ; i < NR_CPUS; i++) {
-		if (cpu_online(i))
-		len += sprintf(buffer + len, "cpu%d %lu %lu\n",
-			i,
-			jiffies_to_clock_t(task->per_cpu_utime[i]),
-			jiffies_to_clock_t(task->per_cpu_stime[i]));
-
-	}
-	return len;
-}
-#endif
===== fs/proc/base.c 1.26 vs edited =====
--- 1.26/fs/proc/base.c	Wed May 22 08:48:14 2002
+++ edited/fs/proc/base.c	Tue Jul 16 00:36:12 2002
@@ -52,7 +52,6 @@
 	PROC_PID_STAT,
 	PROC_PID_STATM,
 	PROC_PID_MAPS,
-	PROC_PID_CPU,
 	PROC_PID_MOUNTS,
 	PROC_PID_FD_DIR = 0x8000,	/* 0x8000-0xffff */
 };
@@ -72,9 +71,6 @@
   E(PROC_PID_CMDLINE,	"cmdline",	S_IFREG|S_IRUGO),
   E(PROC_PID_STAT,	"stat",		S_IFREG|S_IRUGO),
   E(PROC_PID_STATM,	"statm",	S_IFREG|S_IRUGO),
-#ifdef CONFIG_SMP
-  E(PROC_PID_CPU,	"cpu",		S_IFREG|S_IRUGO),
-#endif
   E(PROC_PID_MAPS,	"maps",		S_IFREG|S_IRUGO),
   E(PROC_PID_MEM,	"mem",		S_IFREG|S_IRUSR|S_IWUSR),
   E(PROC_PID_CWD,	"cwd",		S_IFLNK|S_IRWXUGO),
@@ -1010,12 +1006,7 @@
 		case PROC_PID_MAPS:
 			inode->i_fop = &proc_maps_operations;
 			break;
-#ifdef CONFIG_SMP
-		case PROC_PID_CPU:
-			inode->i_fop = &proc_info_file_operations;
-			ei->op.proc_read = proc_pid_cpu;
-			break;
-#endif
+
 		case PROC_PID_MEM:
 			inode->i_op = &proc_mem_inode_operations;
 			inode->i_fop = &proc_mem_operations;
===== include/linux/sched.h 1.70 vs edited =====
--- 1.70/include/linux/sched.h	Thu Jul  4 22:33:26 2002
+++ edited/include/linux/sched.h	Tue Jul 16 00:35:26 2002
@@ -311,7 +311,6 @@
 	struct timer_list real_timer;
 	unsigned long utime, stime, cutime, cstime;
 	unsigned long start_time;
-	long per_cpu_utime[NR_CPUS], per_cpu_stime[NR_CPUS];
 /* mm fault and swap info: this can arguably be seen as either mm-specific or thread-specific */
 	unsigned long min_flt, maj_flt, nswap, cmin_flt, cmaj_flt, cnswap;
 	int swappable:1;
===== kernel/fork.c 1.49 vs edited =====
--- 1.49/kernel/fork.c	Mon Jul  1 14:41:36 2002
+++ edited/kernel/fork.c	Tue Jul 16 00:35:26 2002
@@ -688,16 +688,7 @@
 	p->tty_old_pgrp = 0;
 	p->utime = p->stime = 0;
 	p->cutime = p->cstime = 0;
-#ifdef CONFIG_SMP
-	{
-		int i;
-
-		/* ?? should we just memset this ?? */
-		for(i = 0; i < NR_CPUS; i++)
-			p->per_cpu_utime[i] = p->per_cpu_stime[i] = 0;
-		spin_lock_init(&p->sigmask_lock);
-	}
-#endif
+	spin_lock_init(&p->sigmask_lock);
 	p->array = NULL;
 	p->lock_depth = -1;		/* -1 = no lock */
 	p->start_time = jiffies;
===== kernel/timer.c 1.17 vs edited =====
--- 1.17/kernel/timer.c	Mon Jul  1 14:41:36 2002
+++ edited/kernel/timer.c	Tue Jul 16 00:35:26 2002
@@ -569,8 +569,6 @@
 void update_one_process(struct task_struct *p, unsigned long user,
 			unsigned long system, int cpu)
 {
-	p->per_cpu_utime[cpu] += user;
-	p->per_cpu_stime[cpu] += system;
 	do_process_times(p, user, system);
 	do_it_virt(p, user);
 	do_it_prof(p);

Re: [RFC] shrink task_struct by removing per_cpu utime and stime

[William Lee Irwin III]

On Tue, 2002-07-16 at 08:09, William Lee Irwin III wrote:
>> These statistics severely bloat the task_struct and nothing in
>> userspace can rely on them as they're conditional on CONFIG_SMP. If
>> anyone is using them (or just wants them around), please speak up.

On Tue, Jul 16, 2002 at 11:11:06AM +0100, Alan Cox wrote:
> User space can rely on them because it can check if the data is present.
> Some of the graphical process monitors dump per cpu utime/stime. Its
> sometimes a good way to cringe at our SMP balancing algorithms in 2.4

If that's a "no" I can deal with it. I'm just cringing at its space
consumption and I guess we all know how oversensitive I am to that =).


Cheers,
Bill

Re: [RFC] shrink task_struct by removing per_cpu utime and stime

[William Lee Irwin III]

On Tue, Jul 16, 2002 at 11:12:32AM +0100, Alan Cox wrote:
> A PS: to that. I'm not opposed to removing them. I'd prefer them left
> around in the kernel debugging options though

In that case, I can make it conditional on something like
CONFIG_DEBUG_SCHED, which option of course would go in the "Kernel Hacking"
section.


Cheers,
Bill

Re: [RFC] shrink task_struct by removing per_cpu utime and stime

[Alan Cox]

On Tue, 2002-07-16 at 08:09, William Lee Irwin III wrote:
> These statistics severely bloat the task_struct and nothing in
> userspace can rely on them as they're conditional on CONFIG_SMP. If
> anyone is using them (or just wants them around), please speak up.

User space can rely on them because it can check if the data is present.
Some of the graphical process monitors dump per cpu utime/stime. Its
sometimes a good way to cringe at our SMP balancing algorithms in 2.4

Re: [RFC] shrink task_struct by removing per_cpu utime and stime

[Alan Cox]

A PS: to that. I'm not opposed to removing them. I'd prefer them left
around in the kernel debugging options though