Andrew, Bill,
I had to learn from Michael Hohnbaum that you've eliminated the per
CPU time statistics in 2.5.50 (akpm changeset from Nov. 26). Reading
the cset comments I understood that the motivation was to save
8*NR_CPUS bytes of memory in the task_struct. Maybe that was really an
issue at the time when Bill suggested the patch (July), but in the
mean time we got configurable NR_CPUS (October) and that small amount
of additional memory really doesn't matter. Most people running SMP
have 2 CPUs.
I wasn't aware of the patch and the RFC from Bill, otherwise I would
have "shouted" long time ago. My fault... BTW: did that RFC go to the
LSE mailing list, too? I can't remember. But that's the place were I'd
expect to find people interested in such issues.
When digging in the kernel archives I found:
wli> On Tue, Jul 16, 2002 at 11:12:32AM +0100, Alan Cox wrote:
wli> > A PS: to that. I'm not opposed to removing them. I'd prefer them l=
eft
wli> > around in the kernel debugging options though
wli>=20
wli> In that case, I can make it conditional on something like
wli> CONFIG_DEBUG_SCHED, which option of course would go in the "Kernel H=
acking"
wli> section.
wli>=20
wli> Cheers,
wli> Bill
I find this idea better than just eliminating the only way of finding
out on which CPUs a task has spent its time. This is an essential
question when investigating the performance on SMP and NUMA systems.
For those who miss this feature I'm attaching a patch doing what wli
suggested. The config option is CONFIG_CPUS_STAT and can be found in
the "Kernel Hacking" menu, as wli suggested. Just didn't like
DEBUG_SCHED, we want to monitor the statistics and this is not
necessarily related to bugs in the scheduler. Also added as last line
in /proc/pid/cpu the current CPU of the task. It's often needed and
/proc/pid/stat is much too cryptic.
Regards,
Erich
--------------Boundary-00=_R0IL0IH97J1G7SCM9EHG
Content-Type: text/x-diff;
charset="iso-8859-15";
name="cputimes_stat-2.5.50.patch"
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="cputimes_stat-2.5.50.patch"
diff -urN a/arch/alpha/Kconfig b/arch/alpha/Kconfig
--- a/arch/alpha/Kconfig 2002-11-27 23:36:17.000000000 +0100
+++ b/arch/alpha/Kconfig 2002-12-04 13:16:56.000000000 +0100
@@ -997,6 +997,14 @@
Say Y here if you are developing drivers or trying to debug and
identify kernel problems.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on DEBUG_KERNEL && SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config MATHEMU
tristate "Kernel FP software completion" if DEBUG_KERNEL
default y if !DEBUG_KERNEL
diff -urN a/arch/i386/Kconfig b/arch/i386/Kconfig
--- a/arch/i386/Kconfig 2002-11-27 23:35:50.000000000 +0100
+++ b/arch/i386/Kconfig 2002-12-04 13:13:07.000000000 +0100
@@ -1551,6 +1551,14 @@
Say Y here if you are developing drivers or trying to debug and
identify kernel problems.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on DEBUG_KERNEL && SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config DEBUG_STACKOVERFLOW
bool "Check for stack overflows"
depends on DEBUG_KERNEL
diff -urN a/arch/ia64/Kconfig b/arch/ia64/Kconfig
--- a/arch/ia64/Kconfig 2002-11-27 23:36:20.000000000 +0100
+++ b/arch/ia64/Kconfig 2002-12-04 13:13:43.000000000 +0100
@@ -813,6 +813,14 @@
Say Y here if you are developing drivers or trying to debug and
identify kernel problems.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on DEBUG_KERNEL && SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config KALLSYMS
bool "Load all symbols for debugging/kksymoops"
depends on DEBUG_KERNEL
diff -urN a/arch/mips/Kconfig b/arch/mips/Kconfig
--- a/arch/mips/Kconfig 2002-11-27 23:36:00.000000000 +0100
+++ b/arch/mips/Kconfig 2002-12-04 13:19:56.000000000 +0100
@@ -1284,6 +1284,14 @@
Say Y here if you are compiling the kernel on a different
architecture than the one it is intended to run on.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config REMOTE_DEBUG
bool "Remote GDB kernel debugging"
depends on SERIAL=y || AU1000_UART
diff -urN a/arch/mips64/Kconfig b/arch/mips64/Kconfig
--- a/arch/mips64/Kconfig 2002-11-27 23:35:55.000000000 +0100
+++ b/arch/mips64/Kconfig 2002-12-04 13:20:09.000000000 +0100
@@ -692,6 +692,14 @@
Say Y here if you are compiling the kernel on a different
architecture than the one it is intended to run on.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config MIPS_FPE_MODULE
bool "Build fp exception handler module"
depends on MODULES
diff -urN a/arch/parisc/Kconfig b/arch/parisc/Kconfig
--- a/arch/parisc/Kconfig 2002-11-27 23:36:05.000000000 +0100
+++ b/arch/parisc/Kconfig 2002-12-04 13:18:46.000000000 +0100
@@ -415,6 +415,14 @@
Say Y here if you are developing drivers or trying to debug and
identify kernel problems.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on DEBUG_KERNEL && SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config DEBUG_SLAB
bool "Debug memory allocations"
depends on DEBUG_KERNEL
diff -urN a/arch/ppc/Kconfig b/arch/ppc/Kconfig
--- a/arch/ppc/Kconfig 2002-11-27 23:36:22.000000000 +0100
+++ b/arch/ppc/Kconfig 2002-12-04 13:19:29.000000000 +0100
@@ -1789,6 +1789,14 @@
config DEBUG_KERNEL
bool "Kernel debugging"
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on DEBUG_KERNEL && SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config DEBUG_SLAB
bool "Debug memory allocations"
depends on DEBUG_KERNEL
diff -urN a/arch/ppc64/Kconfig b/arch/ppc64/Kconfig
--- a/arch/ppc64/Kconfig 2002-11-27 23:36:01.000000000 +0100
+++ b/arch/ppc64/Kconfig 2002-12-04 13:20:37.000000000 +0100
@@ -499,6 +499,14 @@
config DEBUG_KERNEL
bool "Kernel debugging"
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on DEBUG_KERNEL && SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config DEBUG_SLAB
bool "Debug memory allocations"
depends on DEBUG_KERNEL
diff -urN a/arch/s390/Kconfig b/arch/s390/Kconfig
--- a/arch/s390/Kconfig 2002-11-27 23:35:57.000000000 +0100
+++ b/arch/s390/Kconfig 2002-12-04 13:21:32.000000000 +0100
@@ -303,6 +303,14 @@
keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
unless you really know what this hack does.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
endmenu
source "security/Kconfig"
diff -urN a/arch/s390x/Kconfig b/arch/s390x/Kconfig
--- a/arch/s390x/Kconfig 2002-11-27 23:36:01.000000000 +0100
+++ b/arch/s390x/Kconfig 2002-12-04 13:22:18.000000000 +0100
@@ -312,6 +312,14 @@
keys are documented in <file:Documentation/sysrq.txt>. Don't say Y
unless you really know what this hack does.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
endmenu
source "security/Kconfig"
diff -urN a/arch/sparc/Kconfig b/arch/sparc/Kconfig
--- a/arch/sparc/Kconfig 2002-11-27 23:35:45.000000000 +0100
+++ b/arch/sparc/Kconfig 2002-12-04 13:23:08.000000000 +0100
@@ -1408,6 +1408,14 @@
config DEBUG_SLAB
bool "Debug memory allocations"
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config MAGIC_SYSRQ
bool "Magic SysRq key"
help
diff -urN a/arch/sparc64/Kconfig b/arch/sparc64/Kconfig
--- a/arch/sparc64/Kconfig 2002-11-27 23:36:18.000000000 +0100
+++ b/arch/sparc64/Kconfig 2002-12-04 13:23:51.000000000 +0100
@@ -1658,6 +1658,14 @@
allocation as well as poisoning memory on free to catch use of freed
memory.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on DEBUG_KERNEL && SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config MAGIC_SYSRQ
bool "Magic SysRq key"
depends on DEBUG_KERNEL
diff -urN a/arch/um/Kconfig b/arch/um/Kconfig
--- a/arch/um/Kconfig 2002-11-27 23:36:00.000000000 +0100
+++ b/arch/um/Kconfig 2002-12-04 13:24:32.000000000 +0100
@@ -154,6 +154,14 @@
config DEBUG_SLAB
bool "Debug memory allocations"
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config DEBUGSYM
bool "Enable kernel debugging symbols"
diff -urN a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig
--- a/arch/x86_64/Kconfig 2002-11-27 23:36:17.000000000 +0100
+++ b/arch/x86_64/Kconfig 2002-12-04 13:25:28.000000000 +0100
@@ -694,6 +694,14 @@
Say Y here if you are developing drivers or trying to debug and
identify kernel problems.
+config CPUS_STAT
+ bool "Per CPU user and system time statistics"
+ depends on DEBUG_KERNEL && SMP
+ help
+ Say Y here to let the kernel gather per CPU user and system
+ time statistics for each task. This can be accessed in
+ /proc/pid/cpu.
+
config DEBUG_SLAB
bool "Debug memory allocations"
depends on DEBUG_KERNEL
diff -urN a/fs/proc/array.c b/fs/proc/array.c
--- a/fs/proc/array.c 2002-11-27 23:36:05.000000000 +0100
+++ b/fs/proc/array.c 2002-12-04 12:59:16.000000000 +0100
@@ -597,3 +597,26 @@
out:
return retval;
}
+
+#ifdef CONFIG_CPUS_STAT
+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]));
+
+ }
+ len += sprintf(buffer + len, "current_cpu %d\n",task_cpu(task));
+ return len;
+}
+#endif
diff -urN a/fs/proc/base.c b/fs/proc/base.c
--- a/fs/proc/base.c 2002-11-27 23:36:06.000000000 +0100
+++ b/fs/proc/base.c 2002-12-04 13:00:17.000000000 +0100
@@ -55,6 +55,7 @@
PROC_PID_STAT,
PROC_PID_STATM,
PROC_PID_MAPS,
+ PROC_PID_CPU,
PROC_PID_MOUNTS,
PROC_PID_WCHAN,
PROC_PID_FD_DIR = 0x8000, /* 0x8000-0xffff */
@@ -75,6 +76,9 @@
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_CPUS_STAT
+ 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),
@@ -1026,7 +1030,12 @@
case PROC_PID_MAPS:
inode->i_fop = &proc_maps_operations;
break;
-
+#ifdef CONFIG_CPUS_STAT
+ 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;
diff -urN a/include/linux/sched.h b/include/linux/sched.h
--- a/include/linux/sched.h 2002-11-27 23:35:49.000000000 +0100
+++ b/include/linux/sched.h 2002-12-04 13:01:34.000000000 +0100
@@ -342,6 +342,9 @@
struct timer_list real_timer;
unsigned long utime, stime, cutime, cstime;
unsigned long start_time;
+#ifdef CONFIG_CPUS_STAT
+ long per_cpu_utime[NR_CPUS], per_cpu_stime[NR_CPUS];
+#endif
/* 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;
diff -urN a/kernel/fork.c b/kernel/fork.c
--- a/kernel/fork.c 2002-11-27 23:35:49.000000000 +0100
+++ b/kernel/fork.c 2002-12-04 13:02:53.000000000 +0100
@@ -794,6 +794,14 @@
p->tty_old_pgrp = 0;
p->utime = p->stime = 0;
p->cutime = p->cstime = 0;
+#ifdef CONFIG_CPUS_STAT
+ {
+ int i;
+
+ for(i = 0; i < NR_CPUS; i++)
+ p->per_cpu_utime[i] = p->per_cpu_stime[i] = 0;
+ }
+#endif
p->array = NULL;
p->lock_depth = -1; /* -1 = no lock */
p->start_time = jiffies;
diff -urN a/kernel/timer.c b/kernel/timer.c
--- a/kernel/timer.c 2002-11-27 23:35:54.000000000 +0100
+++ b/kernel/timer.c 2002-12-04 13:03:26.000000000 +0100
@@ -694,6 +694,10 @@
void update_one_process(struct task_struct *p, unsigned long user,
unsigned long system, int cpu)
{
+#ifdef CONFIG_CPUS_STAT
+ p->per_cpu_utime[cpu] += user;
+ p->per_cpu_stime[cpu] += system;
+#endif
do_process_times(p, user, system);
do_it_virt(p, user);
do_it_prof(p);
--------------Boundary-00=_R0IL0IH97J1G7SCM9EHG--
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