lkml.org 
[lkml]   [2006]   [Jan]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [Patch 6/6] Delay accounting: Connector interface
Shailabh Nagar wrote:
>Changes since 11/14/05:
>
>- explicit versioning of statistics data returned
>- new command type for returning per-tgid stats
>- for cpu running time, use tsk->sched_info.cpu_time (collected by schedstats)
>
>First post 11/14/05
>
>delayacct-connector.patch
>
>Creates a connector interface for getting delay and cpu statistics of tasks
>during their lifetime and when they exit. The cpu stats are available only if
>CONFIG_SCHEDSTATS is enabled.
>
>When a task is alive, userspace can get its stats by sending a command
>containing its pid. Sending a tgid returns the sum of stats of the tasks
>belonging to that tgid (where such a sum makes sense). Together, the command
>interface allows stats for a large number of tasks to be collected more
>efficiently than would be possible through /proc or any per-pid interface.
>
>The connector interface also sends the stats for each task to userspace when
>the task is exiting. This permits fine-grain accounting for short-lived tasks,
>which is important if userspace is doing its own aggregation of statistics
>based on some grouping of tasks (e.g. CSA jobs, ELSA banks or CKRM classes).
>
>While this patch is included as part of the delay stats collection patches,
>it is intended for general use by any kernel component that needs per-pid/tgid
>stats sent at task exit. This limits the increase in connectors called on task
>exit, atleast for stats collection purposes.
>
>Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
>
> drivers/connector/Kconfig | 9 +
> drivers/connector/Makefile | 1
> drivers/connector/cn_stats.c | 243 +++++++++++++++++++++++++++++++++++++++++++
> include/linux/cn_stats.h | 115 ++++++++++++++++++++
> include/linux/connector.h | 4
> kernel/exit.c | 2
> 6 files changed, 374 insertions(+)
>
>Index: linux-2.6.15-rc7/drivers/connector/Kconfig
>===================================================================
>--- linux-2.6.15-rc7.orig/drivers/connector/Kconfig
>+++ linux-2.6.15-rc7/drivers/connector/Kconfig
>@@ -18,4 +18,13 @@ config PROC_EVENTS
> Provide a connector that reports process events to userspace. Send
> events such as fork, exec, id change (uid, gid, suid, etc), and exit.
>
>+config STATS_CONNECTOR
>+ bool "Report per-task statistics to userspace"
>+ depends on CONNECTOR=y && TASK_DELAY_ACCT
>+ ---help---
>+ Provide a connector interface that reports per-task statistics to
>+ userspace. While a task is running, userspace can get the stats by
>+ sending a command to the connector. At task exit, the final value of
>+ the stats is sent automatically.
>+
> endmenu
>Index: linux-2.6.15-rc7/drivers/connector/Makefile
>===================================================================
>--- linux-2.6.15-rc7.orig/drivers/connector/Makefile
>+++ linux-2.6.15-rc7/drivers/connector/Makefile
>@@ -1,4 +1,5 @@
> obj-$(CONFIG_CONNECTOR) += cn.o
>+obj-$(CONFIG_STATS_CONNECTOR) += cn_stats.o
> obj-$(CONFIG_PROC_EVENTS) += cn_proc.o
>
> cn-y += cn_queue.o connector.o
>Index: linux-2.6.15-rc7/include/linux/cn_stats.h
>===================================================================
>--- /dev/null
>+++ linux-2.6.15-rc7/include/linux/cn_stats.h
>@@ -0,0 +1,115 @@
>+/*
>+ * cn_stats.h - Task statistics connector
>+ *
>+ * Copyright (C) Shailabh Nagar, IBM Corp. 2005
>+ * Based on work by Matt Helsley, Nguyen Anh Quynh and Guillaume Thouvenin
>+ *
>+ * This program is free software; you can redistribute it and/or modify
>+ * it under the terms of the GNU General Public License as published by
>+ * the Free Software Foundation; either version 2 of the License, or
>+ * (at your option) any later version.
>+ *
>+ * This program is distributed in the hope that it will be useful,
>+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
>+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>+ * GNU General Public License for more details.
>+ */
>+
>+#ifndef CN_STATS_H
>+#define CN_STATS_H
>+
>+#include <linux/types.h>
>+#include <linux/connector.h>
>+
>+
>+/* Format for per-task data returned to userland when
>+ * - a task exits
>+ * - listener requests stats for all tasks
>+ *
>+ * The struct is versioned. Newer versions should only add fields to
>+ * the bottom of the struct to maintain backward compatibility.
>+ *
>+ * To create the next version, bump up the version count macro
>+ * and delineate the start of newly added fields with a comment indicating the
>+ * version number.
>+ */
>+#define CNSTATS_DATA_VERSION 1
>+
>+struct cnstats_data {
>+
>+ /* Version 1 */
>+ pid_t pid;
>+ pid_t tgid;
>+
>+ /* *_delay_total is cumulative delay (in nanosecs) of a
>+ * task waiting for cpu to be available, block io
>+ * completion, page fault to be serviced etc.
>+ * *_count is number of delay intervals recorded.
>+ * cpu_run_total is cumulative cpu run time, measured by timestamp
>+ * intervals and hence more accurate than sampling-based cpu times.
>+ * All *_total values are in nanoseconds though cpu data may not be
>+ * collected at that granularity.
>+ */
>+
>+ __u64 cpu_count;
>+#define CNSTATS_NOCPUSTATS 1
>+ __u64 cpu_run_total;
>+ __u64 cpu_delay_total;
>+
>+ __u64 blkio_count;
>+ __u64 blkio_delay_total;
>+ __u64 swapin_count;
>+ __u64 swapin_delay_total;
>+
>+};
>+
>+
>+/*
>+ * Commands sent from userspace
>+ */
>+
>+struct cnstats_cmd {
>+ enum intype {
>+ CNSTATS_CMD_LISTEN = 1, /* Start listening on connector */
>+ CNSTATS_CMD_IGNORE, /* Stop listening */
>+ CNSTATS_CMD_STATS_PID, /* Stats for a pid */
>+ CNSTATS_CMD_STATS_TGID, /* Stats for a tgid */
>+ } intype;
>+
>+ union {
>+ pid_t pid;
>+ pid_t tgid;
>+ } param;
>+};
>+
>+/*
>+ * Response or data sent from kernel
>+ * Versioned for backward compatibility
>+ */
>+
>+struct cnstats {
>+ __u32 version;
>+ enum outtype {
>+ CNSTATS_DATA_NONE = 1, /* Control cmd response */
>+ CNSTATS_DATA_EXIT, /* Exiting task's stats */
>+ CNSTATS_DATA_PID, /* per-pid data cmd response*/
>+ CNSTATS_DATA_TGID, /* per-tgid data cmd response*/
>+ } outtype;
>+ union {
>+ struct cnstats_ack {
>+ __u32 err;
>+ } ack;
>+
>+ struct cnstats_data stats;
>+ } data;
>+};
>+
>+#ifdef __KERNEL__
>+#ifdef CONFIG_STATS_CONNECTOR
>+void cnstats_exit_connector(struct task_struct *tsk);
>+#else
>+static inline void cnstats_exit_connector(struct task_struct *tsk)
>+{}
>+#endif /* CONFIG_STATS_CONNECTOR */
>+#endif /* __KERNEL__ */
>+#endif /* CN_PROC_H */
>Index: linux-2.6.15-rc7/include/linux/connector.h
>===================================================================
>--- linux-2.6.15-rc7.orig/include/linux/connector.h
>+++ linux-2.6.15-rc7/include/linux/connector.h
>@@ -35,6 +35,10 @@
> #define CN_IDX_CIFS 0x2
> #define CN_VAL_CIFS 0x1
>
>+/* Statistics connector ids */
>+#define CN_IDX_STATS 0x2
>+#define CN_VAL_STATS 0x2
>+
> #define CN_NETLINK_USERS 1
>
> /*
>Index: linux-2.6.15-rc7/drivers/connector/cn_stats.c
>===================================================================
>--- /dev/null
>+++ linux-2.6.15-rc7/drivers/connector/cn_stats.c
>@@ -0,0 +1,243 @@
>+/*
>+ * cn_stats.c - Task statistics connector
>

It looks like you create this file to report task stats through connector
and you include stats for delay accounting you need as a starter.

This sounds like a good approach to me. However, we need to move
where cnstats_exit_connector(tsk) is invoked. See below.
>+ *
>+ * Copyright (C) Shailabh Nagar, IBM Corp. 2005
>+ * Based on work by Matt Helsley, Nguyen Anh Quynh and Guillaume Thouvenin
>+ *
>+ * This program is free software; you can redistribute it and/or modify
>+ * it under the terms of the GNU General Public License as published by
>+ * the Free Software Foundation; either version 2 of the License, or
>+ * (at your option) any later version.
>+ *
>+ * This program is distributed in the hope that it will be useful,
>+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
>+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
>+ * GNU General Public License for more details.
>+ *
>+ */
>+
>+#include <linux/module.h>
>+#include <linux/kernel.h>
>+#include <linux/init.h>
>+#include <linux/cn_stats.h>
>+#include <asm/atomic.h>
>+
>+#define CN_STATS_NOCPU (-1)
>+#define CN_STATS_NOACK 0
>+#define CN_STATS_MSG_SIZE (sizeof(struct cn_msg) + sizeof(struct cnstats))
>+
>+static atomic_t cnstats_num_listeners = ATOMIC_INIT(0);
>+static struct cb_id cnstats_id = { CN_IDX_STATS, CN_VAL_STATS };
>+/* cnstats_counts is used as the sequence number of the netlink message */
>+static DEFINE_PER_CPU(__u32, cnstats_counts) = { 0 };
>+
>+void cnstats_init_msg(struct cn_msg *msg, int seq, int ack)
>+{
>+ memset(msg, 0, CN_STATS_MSG_SIZE);
>+ msg->seq = seq;
>+ msg->ack = ack;
>+ memcpy(&msg->id, &cnstats_id, sizeof(msg->id));
>+ msg->len = sizeof(struct cnstats);
>+}
>+
>+/*
>+ * Accumalate one task's statistics
>+ *
>+ */
>+static inline void cnstats_add_tsk_data(struct cnstats_data *d, struct task_struct *tsk)
>+{
>+ uint64_t tmp;
>+
>+ d->pid = tsk->pid;
>+ d->tgid = tsk->tgid;
>+
>+ /* zero XXX_total,non-zero XXX_count implies XXX stat overflowed */
>+#ifdef CONFIG_SCHEDSTATS
>+ d->cpu_count += tsk->sched_info.pcnt;
>+ tmp = d->cpu_run_total + jiffies_to_usecs(tsk->sched_info.cpu_time)*1000;
>+ d->cpu_run_total = (tmp < d->cpu_run_total)? 0:tmp;
>+ tmp = d->cpu_delay_total + jiffies_to_usecs(tsk->sched_info.run_delay)*1000;
>+ d->cpu_delay_total = (tmp < d->cpu_delay_total)? 0:tmp;
>+#else
>+ /* Non-zero XXX_total,zero XXX_count implies XXX stat unavailable */
>+ d->cpu_count = 0;
>+ d->cpu_run_total = d->cpu_delay_total = CNSTATS_NOCPUSTATS;
>+#endif
>+ spin_lock(&tsk->delays.lock);
>+ tmp = d->blkio_delay_total + tsk->delays.blkio_delay;
>+ d->blkio_delay_total = (tmp < d->blkio_delay_total)? 0:tmp;
>+ tmp = d->swapin_delay_total + tsk->delays.swapin_delay;
>+ d->swapin_delay_total = (tmp < d->swapin_delay_total)? 0:tmp;
>+ d->blkio_count += tsk->delays.blkio_count;
>+ d->swapin_count += tsk->delays.swapin_count;
>+ spin_unlock(&tsk->delays.lock);
>+}
>+
>+/*
>+ * Send acknowledgement (error)
>+ *
>+ */
>+static void cnstats_send_ack(int err, int rcvd_seq, int rcvd_ack)
>+{
>+ __u8 buffer[CN_STATS_MSG_SIZE];
>+ struct cn_msg *msg = (struct cn_msg *)buffer;
>+ struct cnstats *c = (struct cnstats *)msg->data;
>+
>+ cnstats_init_msg(msg, rcvd_seq, rcvd_ack+1);
>+ c->version = CNSTATS_DATA_VERSION;
>+ c->outtype = CNSTATS_DATA_NONE;
>+
>+ /* Following allows other functions to continue returning -ve errors */
>+ c->data.ack.err = abs(err);
>+
>+ cn_netlink_send(msg, CN_IDX_STATS, GFP_KERNEL);
>+}
>+
>+/*
>+ * Send one pid's stats
>+ *
>+ */
>+static int cnstats_send_pid(pid_t pid, int seq, int ack)
>+{
>+ __u8 buffer[CN_STATS_MSG_SIZE];
>+ struct cn_msg *msg = (struct cn_msg *)buffer;
>+ struct cnstats *c = (struct cnstats *)msg->data;
>+ struct cnstats_data *d = (struct cnstats_data *)&c->data.stats;
>+ struct task_struct *tsk;
>+
>+ cnstats_init_msg(msg, seq, ack);
>+ c->version = CNSTATS_DATA_VERSION;
>+ c->outtype = CNSTATS_DATA_PID;
>+
>+ read_lock(&tasklist_lock);
>+ tsk = find_task_by_pid(pid);
>+ if (!tsk) {
>+ read_unlock(&tasklist_lock);
>+ return -ESRCH;
>+ }
>+ get_task_struct(tsk);
>+ read_unlock(&tasklist_lock);
>+
>+ cnstats_add_tsk_data(d, tsk);
>+ put_task_struct(tsk);
>+
>+ return cn_netlink_send(msg, CN_IDX_STATS, GFP_KERNEL);
>+}
>+
>+/*
>+ * Send one tgid's stats (sum of appropriate per-pid stats)
>+ *
>+ */
>+static int cnstats_send_tgid(pid_t tgid, int seq, int ack)
>+{
>+ __u8 buffer[CN_STATS_MSG_SIZE];
>+ struct cn_msg *msg = (struct cn_msg *)buffer;;
>+ struct cnstats *c = (struct cnstats *)msg->data;
>+ struct cnstats_data *d = (struct cnstats_data *)&c->data.stats;
>+ struct task_struct *first, *tsk;
>+
>+ cnstats_init_msg(msg, seq, ack);
>+ c->version = CNSTATS_DATA_VERSION;
>+ c->outtype = CNSTATS_DATA_TGID;
>+
>+ read_lock(&tasklist_lock);
>+ first = tsk = find_task_by_pid(tgid);
>+ if (!first) {
>+ read_unlock(&tasklist_lock);
>+ return -ESRCH;
>+ }
>+ do
>+ cnstats_add_tsk_data(d, tsk);
>+ while_each_thread(first, tsk);
>+ read_unlock(&tasklist_lock);
>+
>+ d->pid = -1;
>+ d->tgid = tgid;
>+
>+ return cn_netlink_send(msg, CN_IDX_STATS, GFP_KERNEL);
>+}
>+
>+/***
>+ * cnstats_ctl - handle command sent via CN_IDX_STATS connector
>+ * @data: command
>+ */
>+static void cnstats_ctl(void *data)
>+{
>+ struct cn_msg *msg = data;
>+ struct cnstats_cmd *cmd;
>+ int err = 0;
>+
>+ if (msg->len != sizeof(*cmd))
>+ return;
>+
>+ cmd = (struct cnstats_cmd *)msg->data;
>+ switch (cmd->intype) {
>+ case CNSTATS_CMD_LISTEN:
>+ atomic_inc(&cnstats_num_listeners);
>+ break;
>+
>+ case CNSTATS_CMD_IGNORE:
>+ atomic_dec(&cnstats_num_listeners);
>+ break;
>+
>+ case CNSTATS_CMD_STATS_PID:
>+ if (atomic_read(&cnstats_num_listeners) < 1)
>+ return;
>+ err = cnstats_send_pid(cmd->param.pid, msg->seq, msg->ack+1);
>+ if (!err)
>+ return;
>+ break;
>+
>+ case CNSTATS_CMD_STATS_TGID:
>+ if (atomic_read(&cnstats_num_listeners) < 1)
>+ return;
>+ err = cnstats_send_tgid(cmd->param.pid, msg->seq, msg->ack+1);
>+ if (!err)
>+ return;
>+ break;
>+
>+ default:
>+ err = -EINVAL;
>+ break;
>+ }
>+ cnstats_send_ack(err, msg->seq, msg->ack);
>+}
>+
>+/***
>+ * cnstats_exit_connector - send task's statistics to userspace when it exits
>+ * @tsk: exiting task
>+ */
>+void cnstats_exit_connector(struct task_struct *tsk)
>+{
>+ int seq;
>+ __u8 buffer[CN_STATS_MSG_SIZE];
>+ struct cn_msg *msg = (struct cn_msg *)buffer;
>+ struct cnstats *c = (struct cnstats *)msg->data;
>+ struct cnstats_data *d = (struct cnstats_data *)&c->data.stats;
>+
>+ if (atomic_read(&cnstats_num_listeners) < 1)
>+ return;
>+
>+ seq = get_cpu_var(cnstats_counts)++;
>+ put_cpu_var(cnstats_counts);
>+
>+ cnstats_init_msg(msg, seq, CN_STATS_NOACK);
>+ c->version = CNSTATS_DATA_VERSION;
>+ c->outtype = CNSTATS_DATA_EXIT;
>+ cnstats_add_tsk_data(d, tsk);
>+
>+ cn_netlink_send(msg, CN_IDX_STATS, GFP_KERNEL);
>+}
>+
>+static int __init cnstats_init(void)
>+{
>+ int err;
>+
>+ if ((err = cn_add_callback(&cnstats_id, "cn_stats", &cnstats_ctl))) {
>+ printk(KERN_WARNING "cn_stats failed to register\n");
>+ return err;
>+ }
>+ return 0;
>+}
>+
>+module_init(cnstats_init);
>Index: linux-2.6.15-rc7/kernel/exit.c
>===================================================================
>--- linux-2.6.15-rc7.orig/kernel/exit.c
>+++ linux-2.6.15-rc7/kernel/exit.c
>@@ -29,6 +29,7 @@
> #include <linux/syscalls.h>
> #include <linux/signal.h>
> #include <linux/cn_proc.h>
>+#include <linux/cn_stats.h>
>
> #include <asm/uaccess.h>
> #include <asm/unistd.h>
>@@ -865,6 +866,7 @@ fastcall NORET_TYPE void do_exit(long co
>
> tsk->exit_code = code;
> proc_exit_connector(tsk);
>+ cnstats_exit_connector(tsk);
>

We need to move both proc_exit_connector(tsk) and
cnstats_exit_connector(tsk) up to before exit_mm(tsk) statement.
There are task statistics collected in task->mm and those stats
will be lost after exit_mm(tsk).

Thanks,
- jay

> exit_notify(tsk);
> #ifdef CONFIG_NUMA
> mpol_free(tsk->mempolicy);
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
>the body of a message to majordomo@vger.kernel.org
>More majordomo info at http://vger.kernel.org/majordomo-info.html
>Please read the FAQ at http://www.tux.org/lkml/
>

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2006-01-04 20:07    [W:2.114 / U:0.264 seconds]
©2003-2014 Jasper Spaans. Advertise on this site