Hi Paul,
I liked the basic idea of accounting for cpu cycles. But, i see it
similar to the delay accounting feature that Vatsa pointed to than to be
part of Resource Groups, as the main purpose of RG is resource
management than resource monitoring.
Delay accounting stats and RG are intended to be used together.
Basically, the user space app forms the group and associates it with an
RG, sums up delay stats for each task in the group to get the collective
delay information for the group.
chandra
On Fri, 2006-08-04 at 18:33 -0700, Paul Menage wrote:
> One of the arguments presented against merging the Resource Groups
> core is the lack of resource controllers that are in a state where
> they're ready to be merged.
>
> Here's a very simple resource "controller" that simply accounts the
> CPU time consumed by the tasks in a resource group, and reports it via
> the stats interface. It has no shares or other configuration, but also
> has nothing intrusive in the kernel apart from a couple of calls to an
> accounting function in the existing time accounting in sched.c
>
> It's something that could be useful for any job control system.
> Obviously a proper CPU scheduler with QoS isolation is better, but (in
> the absence of such a scheduler that's ready for merging), right now
> tracking the CPU cycles consumed by a group of processes involves lots
> of expensive /proc scraping. (It's certainly something that we'd find
> useful).
>
> How about adding this alongside the numtasks controller as an example
> of a simple but useful controller?
>
> Paul
>
> diff -Naur -X /home/menage/dontdiff
> linux-2.6.17.7-clean/include/linux/cpu_acct.h
> linux-2.6.17.7/include/linux/cpu_acct.h
> --- linux-2.6.17.7-clean/include/linux/cpu_acct.h 1969-12-31
> 16:00:00.000000000 -0800
> +++ linux-2.6.17.7/include/linux/cpu_acct.h 2006-08-03 21:59:04.000000000
> -0700
> @@ -0,0 +1,10 @@
> +
> +#ifndef _LINUX_CPU_ACCT_H
> +#define _LINUX_CPU_ACCT_H
> +
> +#include <linux/res_group_rc.h>
> +#include <asm/cputime.h>
> +
> +extern void cpuacct_charge(struct resource_group *, cputime_t cputime);
> +
> +#endif
> diff -Naur -X /home/menage/dontdiff
> linux-2.6.17.7-clean/kernel/sched.c linux-2.6.17.7/kernel/sched.c
> --- linux-2.6.17.7-clean/kernel/sched.c 2006-07-24 20:36:01.000000000
> -0700
> +++ linux-2.6.17.7/kernel/sched.c 2006-08-03 23:26:03.000000000 -0700
> @@ -50,6 +50,7 @@
> #include <linux/times.h>
> #include <linux/acct.h>
> #include <linux/kprobes.h>
> +#include <linux/cpu_acct.h>
> #include <asm/tlb.h>
>
> #include <asm/unistd.h>
> @@ -2518,6 +2519,8 @@
>
> p->utime = cputime_add(p->utime, cputime);
>
> + cpuacct_charge(p->res_group, cputime);
> +
> /* Add user time to cpustat. */
> tmp = cputime_to_cputime64(cputime);
> if (TASK_NICE(p) > 0)
> @@ -2541,6 +2544,8 @@
>
> p->stime = cputime_add(p->stime, cputime);
>
> + cpuacct_charge(p->res_group, cputime);
> +
> /* Add system time to cpustat. */
> tmp = cputime_to_cputime64(cputime);
> if (hardirq_count() - hardirq_offset)
> --- linux-2.6.17.7-clean/kernel/res_group/Makefile 2006-08-04
> 17:35:52.000000000 -0700
> +++ linux-2.6.17.7/kernel/res_group/Makefile 2006-08-04 17:46:21.000000000
> -0700
> @@ -1,3 +1,4 @@
> obj-y = res_group.o shares.o task.o
> obj-$(CONFIG_RES_GROUPS_NUMTASKS) += numtasks.o
> +obj-$(CONFIG_RES_GROUPS_CPUACCT) += cpu_acct.o
> obj-$(CONFIG_RGCS) += rgcs.o
> --- linux-2.6.17.7-clean/init/Kconfig 2006-08-04 17:35:52.000000000 -0700
> +++ linux-2.6.17.7/init/Kconfig 2006-08-04 17:45:50.000000000 -0700
> @@ -185,6 +185,14 @@
>
> Say N if unsure, Y to use the feature.
>
> +config RES_GROUPS_CPUACCT
> + bool "Simple CPU accounting Resource Controller"
> + depends on RES_GROUPS
> + default y
> + help
> + Provides a simple Resource Controller for monitoring the
> + total CPU consumed by the tasks in a resource group
> +
> endmenu
> config SYSCTL
> bool "Sysctl support"
> --- linux-2.6.17.7-clean/kernel/res_group/cpu_acct.c 1969-12-31
> 16:00:00.000000000 -0800
> +++ linux-2.6.17.7/kernel/res_group/cpu_acct.c 2006-08-04
> 18:07:28.000000000 -0700
> @@ -0,0 +1,121 @@
> +/* cpu_acct.c - CPU accounting resource controller for Resource Groups
> + *
> + * Copyright (C) Google Inc, 2006
> + *
> + */
> +
> +/*
> + * Resource controller for reporting total CPU usage of tasks in a
> + * resource group.
> + */
> +#include <linux/module.h>
> +#include <linux/res_group_rc.h>
> +#include <asm/div64.h>
> +
> +static const char res_ctlr_name[] = "cpuacct";
> +
> +struct cpuacct {
> + struct res_shares shares; // Not really used
> + spinlock_t lock;
> + cputime64_t time; // total time used by this class
> +};
> +
> +struct res_controller cpuacct_ctlr;
> +
> +static struct cpuacct *get_shares_cpuacct(struct res_shares *shares) {
> + if (shares)
> + return container_of(shares, struct cpuacct, shares);
> + return NULL;
> +}
> +
> +static struct cpuacct *get_cpuacct(struct resource_group *rgroup) {
> + return get_shares_cpuacct(get_controller_shares(rgroup,
> + &cpuacct_ctlr));
> +}
> +
> +static struct res_shares *cpuacct_alloc_shares_struct(
> + struct resource_group *rgroup) {
> + struct cpuacct *res;
> +
> + res = kzalloc(sizeof(struct cpuacct), GFP_KERNEL);
> + if (!res) {
> + return NULL;
> + }
> + res->shares.min_shares = SHARE_UNSUPPORTED;
> + res->shares.max_shares = SHARE_UNSUPPORTED;
> + res->shares.child_shares_divisor = SHARE_DEFAULT_DIVISOR;
> + res->shares.unused_min_shares = SHARE_DEFAULT_DIVISOR;
> + spin_lock_init(&res->lock);
> + return &res->shares;
> +}
> +
> +static void cpuacct_free_shares_struct(struct res_shares *shares) {
> + struct cpuacct *res;
> +
> + res = get_shares_cpuacct(shares);
> + kfree(res);
> +}
> +
> +static ssize_t cpuacct_show_stats(struct res_shares *shares,
> + char *buf, size_t buf_size) {
> + struct cpuacct *res;
> + cputime64_t time;
> +
> + res = get_shares_cpuacct(shares);
> + if (!res)
> + return -EINVAL;
> +
> + spin_lock_irq(&res->lock);
> + time = res->time;
> + spin_unlock_irq(&res->lock);
> +
> + time *= 1000;
> + do_div(time, HZ);
> + return snprintf(buf, buf_size, "%s: total_msecs: %llu\n",
> + res_ctlr_name, time);
> +
> +}
> +
> +void cpuacct_charge(struct resource_group * rgroup, cputime_t cputime) {
> + struct cpuacct *res;
> + unsigned long flags;
> +
> + if ((cpuacct_ctlr.ctlr_id == NO_RES_ID) || (rgroup == NULL))
> + return;
> +
> + res = get_cpuacct(rgroup);
> +
> + /* cpuacct not available for this resource group */
> + if (!res)
> + return;
> +
> + spin_lock_irqsave(&res->lock, flags);
> + res->time = cputime64_add(res->time, cputime);
> + spin_unlock_irqrestore(&res->lock, flags);
> +
> +}
> +
> +struct res_controller cpuacct_ctlr = {
> + .name = res_ctlr_name,
> + .depth_supported = 3,
> + .ctlr_id = NO_RES_ID,
> + .alloc_shares_struct = cpuacct_alloc_shares_struct,
> + .free_shares_struct = cpuacct_free_shares_struct,
> + .show_stats = cpuacct_show_stats,
> +};
> +
> +int __init init_cpuacct_res(void) {
> + if (cpuacct_ctlr.ctlr_id != NO_RES_ID)
> + return -EBUSY; /* already registered */
> + return register_controller(&cpuacct_ctlr);
> +}
> +
> +void __exit exit_cpuacct_res(void) {
> + int rc;
> + do {
> + rc = unregister_controller(&cpuacct_ctlr);
> + } while (rc == -EBUSY);
> + BUG_ON(rc != 0);
> +}
> +module_init(init_cpuacct_res)
> +module_exit(exit_cpuacct_res)
>
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--
----------------------------------------------------------------------
Chandra Seetharaman | Be careful what you choose....
- [EMAIL PROTECTED] | .......you may get it.
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