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c3123552 | 1 | ==================== |
db5fed26 | 2 | The struct taskstats |
c3123552 | 3 | ==================== |
db5fed26 JL |
4 | |
5 | This document contains an explanation of the struct taskstats fields. | |
6 | ||
7 | There are three different groups of fields in the struct taskstats: | |
8 | ||
9 | 1) Common and basic accounting fields | |
d9195881 | 10 | If CONFIG_TASKSTATS is set, the taskstats interface is enabled and |
db5fed26 JL |
11 | the common fields and basic accounting fields are collected for |
12 | delivery at do_exit() of a task. | |
13 | 2) Delay accounting fields | |
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14 | These fields are placed between:: |
15 | ||
16 | /* Delay accounting fields start */ | |
17 | ||
18 | and:: | |
19 | ||
20 | /* Delay accounting fields end */ | |
21 | ||
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22 | Their values are collected if CONFIG_TASK_DELAY_ACCT is set. |
23 | 3) Extended accounting fields | |
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24 | These fields are placed between:: |
25 | ||
26 | /* Extended accounting fields start */ | |
27 | ||
28 | and:: | |
29 | ||
30 | /* Extended accounting fields end */ | |
31 | ||
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32 | Their values are collected if CONFIG_TASK_XACCT is set. |
33 | ||
b663a79c MU |
34 | 4) Per-task and per-thread context switch count statistics |
35 | ||
f93f18cd HS |
36 | 5) Time accounting for SMT machines |
37 | ||
016ae219 KK |
38 | 6) Extended delay accounting fields for memory reclaim |
39 | ||
db5fed26 JL |
40 | Future extension should add fields to the end of the taskstats struct, and |
41 | should not change the relative position of each field within the struct. | |
42 | ||
c3123552 | 43 | :: |
db5fed26 | 44 | |
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45 | struct taskstats { |
46 | ||
47 | 1) Common and basic accounting fields:: | |
db5fed26 | 48 | |
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49 | /* The version number of this struct. This field is always set to |
50 | * TAKSTATS_VERSION, which is defined in <linux/taskstats.h>. | |
51 | * Each time the struct is changed, the value should be incremented. | |
52 | */ | |
53 | __u16 version; | |
54 | ||
c3123552 | 55 | /* The exit code of a task. */ |
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56 | __u32 ac_exitcode; /* Exit status */ |
57 | ||
c3123552 | 58 | /* The accounting flags of a task as defined in <linux/acct.h> |
db5fed26 JL |
59 | * Defined values are AFORK, ASU, ACOMPAT, ACORE, and AXSIG. |
60 | */ | |
61 | __u8 ac_flag; /* Record flags */ | |
62 | ||
c3123552 | 63 | /* The value of task_nice() of a task. */ |
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64 | __u8 ac_nice; /* task_nice */ |
65 | ||
c3123552 | 66 | /* The name of the command that started this task. */ |
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67 | char ac_comm[TS_COMM_LEN]; /* Command name */ |
68 | ||
c3123552 | 69 | /* The scheduling discipline as set in task->policy field. */ |
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70 | __u8 ac_sched; /* Scheduling discipline */ |
71 | ||
72 | __u8 ac_pad[3]; | |
73 | __u32 ac_uid; /* User ID */ | |
74 | __u32 ac_gid; /* Group ID */ | |
75 | __u32 ac_pid; /* Process ID */ | |
76 | __u32 ac_ppid; /* Parent process ID */ | |
77 | ||
c3123552 | 78 | /* The time when a task begins, in [secs] since 1970. */ |
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79 | __u32 ac_btime; /* Begin time [sec since 1970] */ |
80 | ||
c3123552 | 81 | /* The elapsed time of a task, in [usec]. */ |
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82 | __u64 ac_etime; /* Elapsed time [usec] */ |
83 | ||
c3123552 | 84 | /* The user CPU time of a task, in [usec]. */ |
db5fed26 JL |
85 | __u64 ac_utime; /* User CPU time [usec] */ |
86 | ||
c3123552 | 87 | /* The system CPU time of a task, in [usec]. */ |
db5fed26 JL |
88 | __u64 ac_stime; /* System CPU time [usec] */ |
89 | ||
c3123552 | 90 | /* The minor page fault count of a task, as set in task->min_flt. */ |
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91 | __u64 ac_minflt; /* Minor Page Fault Count */ |
92 | ||
93 | /* The major page fault count of a task, as set in task->maj_flt. */ | |
94 | __u64 ac_majflt; /* Major Page Fault Count */ | |
95 | ||
96 | ||
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97 | 2) Delay accounting fields:: |
98 | ||
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99 | /* Delay accounting fields start |
100 | * | |
101 | * All values, until the comment "Delay accounting fields end" are | |
102 | * available only if delay accounting is enabled, even though the last | |
103 | * few fields are not delays | |
104 | * | |
105 | * xxx_count is the number of delay values recorded | |
106 | * xxx_delay_total is the corresponding cumulative delay in nanoseconds | |
107 | * | |
108 | * xxx_delay_total wraps around to zero on overflow | |
109 | * xxx_count incremented regardless of overflow | |
110 | */ | |
111 | ||
112 | /* Delay waiting for cpu, while runnable | |
113 | * count, delay_total NOT updated atomically | |
114 | */ | |
115 | __u64 cpu_count; | |
116 | __u64 cpu_delay_total; | |
117 | ||
118 | /* Following four fields atomically updated using task->delays->lock */ | |
119 | ||
120 | /* Delay waiting for synchronous block I/O to complete | |
121 | * does not account for delays in I/O submission | |
122 | */ | |
123 | __u64 blkio_count; | |
124 | __u64 blkio_delay_total; | |
125 | ||
126 | /* Delay waiting for page fault I/O (swap in only) */ | |
127 | __u64 swapin_count; | |
128 | __u64 swapin_delay_total; | |
129 | ||
130 | /* cpu "wall-clock" running time | |
131 | * On some architectures, value will adjust for cpu time stolen | |
132 | * from the kernel in involuntary waits due to virtualization. | |
133 | * Value is cumulative, in nanoseconds, without a corresponding count | |
134 | * and wraps around to zero silently on overflow | |
135 | */ | |
136 | __u64 cpu_run_real_total; | |
137 | ||
138 | /* cpu "virtual" running time | |
139 | * Uses time intervals seen by the kernel i.e. no adjustment | |
140 | * for kernel's involuntary waits due to virtualization. | |
141 | * Value is cumulative, in nanoseconds, without a corresponding count | |
142 | * and wraps around to zero silently on overflow | |
143 | */ | |
144 | __u64 cpu_run_virtual_total; | |
145 | /* Delay accounting fields end */ | |
146 | /* version 1 ends here */ | |
147 | ||
148 | ||
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149 | 3) Extended accounting fields:: |
150 | ||
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151 | /* Extended accounting fields start */ |
152 | ||
153 | /* Accumulated RSS usage in duration of a task, in MBytes-usecs. | |
154 | * The current rss usage is added to this counter every time | |
155 | * a tick is charged to a task's system time. So, at the end we | |
156 | * will have memory usage multiplied by system time. Thus an | |
157 | * average usage per system time unit can be calculated. | |
158 | */ | |
159 | __u64 coremem; /* accumulated RSS usage in MB-usec */ | |
160 | ||
c3123552 | 161 | /* Accumulated virtual memory usage in duration of a task. |
db5fed26 JL |
162 | * Same as acct_rss_mem1 above except that we keep track of VM usage. |
163 | */ | |
164 | __u64 virtmem; /* accumulated VM usage in MB-usec */ | |
165 | ||
c3123552 | 166 | /* High watermark of RSS usage in duration of a task, in KBytes. */ |
db5fed26 JL |
167 | __u64 hiwater_rss; /* High-watermark of RSS usage */ |
168 | ||
c3123552 | 169 | /* High watermark of VM usage in duration of a task, in KBytes. */ |
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170 | __u64 hiwater_vm; /* High-water virtual memory usage */ |
171 | ||
172 | /* The following four fields are I/O statistics of a task. */ | |
173 | __u64 read_char; /* bytes read */ | |
174 | __u64 write_char; /* bytes written */ | |
175 | __u64 read_syscalls; /* read syscalls */ | |
176 | __u64 write_syscalls; /* write syscalls */ | |
177 | ||
178 | /* Extended accounting fields end */ | |
179 | ||
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180 | 4) Per-task and per-thread statistics:: |
181 | ||
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182 | __u64 nvcsw; /* Context voluntary switch counter */ |
183 | __u64 nivcsw; /* Context involuntary switch counter */ | |
184 | ||
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185 | 5) Time accounting for SMT machines:: |
186 | ||
f93f18cd HS |
187 | __u64 ac_utimescaled; /* utime scaled on frequency etc */ |
188 | __u64 ac_stimescaled; /* stime scaled on frequency etc */ | |
189 | __u64 cpu_scaled_run_real_total; /* scaled cpu_run_real_total */ | |
016ae219 | 190 | |
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191 | 6) Extended delay accounting fields for memory reclaim:: |
192 | ||
016ae219 KK |
193 | /* Delay waiting for memory reclaim */ |
194 | __u64 freepages_count; | |
195 | __u64 freepages_delay_total; | |
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196 | |
197 | :: | |
198 | ||
199 | } |