description.go

     1  // Copyright 2020 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package metrics
     6  
     7  import "internal/godebugs"
     8  
     9  // Description describes a runtime metric.
    10  type Description struct {
    11  	// Name is the full name of the metric which includes the unit.
    12  	//
    13  	// The format of the metric may be described by the following regular expression.
    14  	//
    15  	// 	^(?P<name>/[^:]+):(?P<unit>[^:*/]+(?:[*/][^:*/]+)*)$
    16  	//
    17  	// The format splits the name into two components, separated by a colon: a path which always
    18  	// starts with a /, and a machine-parseable unit. The name may contain any valid Unicode
    19  	// codepoint in between / characters, but by convention will try to stick to lowercase
    20  	// characters and hyphens. An example of such a path might be "/memory/heap/free".
    21  	//
    22  	// The unit is by convention a series of lowercase English unit names (singular or plural)
    23  	// without prefixes delimited by '*' or '/'. The unit names may contain any valid Unicode
    24  	// codepoint that is not a delimiter.
    25  	// Examples of units might be "seconds", "bytes", "bytes/second", "cpu-seconds",
    26  	// "byte*cpu-seconds", and "bytes/second/second".
    27  	//
    28  	// For histograms, multiple units may apply. For instance, the units of the buckets and
    29  	// the count. By convention, for histograms, the units of the count are always "samples"
    30  	// with the type of sample evident by the metric's name, while the unit in the name
    31  	// specifies the buckets' unit.
    32  	//
    33  	// A complete name might look like "/memory/heap/free:bytes".
    34  	Name string
    35  
    36  	// Description is an English language sentence describing the metric.
    37  	Description string
    38  
    39  	// Kind is the kind of value for this metric.
    40  	//
    41  	// The purpose of this field is to allow users to filter out metrics whose values are
    42  	// types which their application may not understand.
    43  	Kind ValueKind
    44  
    45  	// Cumulative is whether or not the metric is cumulative. If a cumulative metric is just
    46  	// a single number, then it increases monotonically. If the metric is a distribution,
    47  	// then each bucket count increases monotonically.
    48  	//
    49  	// This flag thus indicates whether or not it's useful to compute a rate from this value.
    50  	Cumulative bool
    51  }
    52  
    53  // The English language descriptions below must be kept in sync with the
    54  // descriptions of each metric in doc.go by running 'go generate'.
    55  var allDesc = []Description{
    56  	{
    57  		Name:        "/cgo/go-to-c-calls:calls",
    58  		Description: "Count of calls made from Go to C by the current process.",
    59  		Kind:        KindUint64,
    60  		Cumulative:  true,
    61  	},
    62  	{
    63  		Name: "/cpu/classes/gc/mark/assist:cpu-seconds",
    64  		Description: "Estimated total CPU time goroutines spent performing GC tasks " +
    65  			"to assist the GC and prevent it from falling behind the application. " +
    66  			"This metric is an overestimate, and not directly comparable to " +
    67  			"system CPU time measurements. Compare only with other /cpu/classes " +
    68  			"metrics.",
    69  		Kind:       KindFloat64,
    70  		Cumulative: true,
    71  	},
    72  	{
    73  		Name: "/cpu/classes/gc/mark/dedicated:cpu-seconds",
    74  		Description: "Estimated total CPU time spent performing GC tasks on " +
    75  			"processors (as defined by GOMAXPROCS) dedicated to those tasks. " +
    76  			"This metric is an overestimate, and not directly comparable to " +
    77  			"system CPU time measurements. Compare only with other /cpu/classes " +
    78  			"metrics.",
    79  		Kind:       KindFloat64,
    80  		Cumulative: true,
    81  	},
    82  	{
    83  		Name: "/cpu/classes/gc/mark/idle:cpu-seconds",
    84  		Description: "Estimated total CPU time spent performing GC tasks on " +
    85  			"spare CPU resources that the Go scheduler could not otherwise find " +
    86  			"a use for. This should be subtracted from the total GC CPU time to " +
    87  			"obtain a measure of compulsory GC CPU time. " +
    88  			"This metric is an overestimate, and not directly comparable to " +
    89  			"system CPU time measurements. Compare only with other /cpu/classes " +
    90  			"metrics.",
    91  		Kind:       KindFloat64,
    92  		Cumulative: true,
    93  	},
    94  	{
    95  		Name: "/cpu/classes/gc/pause:cpu-seconds",
    96  		Description: "Estimated total CPU time spent with the application paused by " +
    97  			"the GC. Even if only one thread is running during the pause, this is " +
    98  			"computed as GOMAXPROCS times the pause latency because nothing else " +
    99  			"can be executing. This is the exact sum of samples in " +
   100  			"/sched/pauses/total/gc:seconds if each sample is multiplied by " +
   101  			"GOMAXPROCS at the time it is taken. This metric is an overestimate, " +
   102  			"and not directly comparable to system CPU time measurements. Compare " +
   103  			"only with other /cpu/classes metrics.",
   104  		Kind:       KindFloat64,
   105  		Cumulative: true,
   106  	},
   107  	{
   108  		Name: "/cpu/classes/gc/total:cpu-seconds",
   109  		Description: "Estimated total CPU time spent performing GC tasks. " +
   110  			"This metric is an overestimate, and not directly comparable to " +
   111  			"system CPU time measurements. Compare only with other /cpu/classes " +
   112  			"metrics. Sum of all metrics in /cpu/classes/gc.",
   113  		Kind:       KindFloat64,
   114  		Cumulative: true,
   115  	},
   116  	{
   117  		Name: "/cpu/classes/idle:cpu-seconds",
   118  		Description: "Estimated total available CPU time not spent executing any Go or Go runtime code. " +
   119  			"In other words, the part of /cpu/classes/total:cpu-seconds that was unused. " +
   120  			"This metric is an overestimate, and not directly comparable to " +
   121  			"system CPU time measurements. Compare only with other /cpu/classes " +
   122  			"metrics.",
   123  		Kind:       KindFloat64,
   124  		Cumulative: true,
   125  	},
   126  	{
   127  		Name: "/cpu/classes/scavenge/assist:cpu-seconds",
   128  		Description: "Estimated total CPU time spent returning unused memory to the " +
   129  			"underlying platform in response eagerly in response to memory pressure. " +
   130  			"This metric is an overestimate, and not directly comparable to " +
   131  			"system CPU time measurements. Compare only with other /cpu/classes " +
   132  			"metrics.",
   133  		Kind:       KindFloat64,
   134  		Cumulative: true,
   135  	},
   136  	{
   137  		Name: "/cpu/classes/scavenge/background:cpu-seconds",
   138  		Description: "Estimated total CPU time spent performing background tasks " +
   139  			"to return unused memory to the underlying platform. " +
   140  			"This metric is an overestimate, and not directly comparable to " +
   141  			"system CPU time measurements. Compare only with other /cpu/classes " +
   142  			"metrics.",
   143  		Kind:       KindFloat64,
   144  		Cumulative: true,
   145  	},
   146  	{
   147  		Name: "/cpu/classes/scavenge/total:cpu-seconds",
   148  		Description: "Estimated total CPU time spent performing tasks that return " +
   149  			"unused memory to the underlying platform. " +
   150  			"This metric is an overestimate, and not directly comparable to " +
   151  			"system CPU time measurements. Compare only with other /cpu/classes " +
   152  			"metrics. Sum of all metrics in /cpu/classes/scavenge.",
   153  		Kind:       KindFloat64,
   154  		Cumulative: true,
   155  	},
   156  	{
   157  		Name: "/cpu/classes/total:cpu-seconds",
   158  		Description: "Estimated total available CPU time for user Go code " +
   159  			"or the Go runtime, as defined by GOMAXPROCS. In other words, GOMAXPROCS " +
   160  			"integrated over the wall-clock duration this process has been executing for. " +
   161  			"This metric is an overestimate, and not directly comparable to " +
   162  			"system CPU time measurements. Compare only with other /cpu/classes " +
   163  			"metrics. Sum of all metrics in /cpu/classes.",
   164  		Kind:       KindFloat64,
   165  		Cumulative: true,
   166  	},
   167  	{
   168  		Name: "/cpu/classes/user:cpu-seconds",
   169  		Description: "Estimated total CPU time spent running user Go code. This may " +
   170  			"also include some small amount of time spent in the Go runtime. " +
   171  			"This metric is an overestimate, and not directly comparable to " +
   172  			"system CPU time measurements. Compare only with other /cpu/classes " +
   173  			"metrics.",
   174  		Kind:       KindFloat64,
   175  		Cumulative: true,
   176  	},
   177  	{
   178  		Name: "/gc/cleanups/executed:cleanups",
   179  		Description: "Approximate total count of cleanup functions (created by runtime.AddCleanup) " +
   180  			"executed by the runtime. Subtract /gc/cleanups/queued:cleanups to approximate " +
   181  			"cleanup queue length. Useful for detecting slow cleanups holding up the queue.",
   182  		Kind:       KindUint64,
   183  		Cumulative: true,
   184  	},
   185  	{
   186  		Name: "/gc/cleanups/queued:cleanups",
   187  		Description: "Approximate total count of cleanup functions (created by runtime.AddCleanup) " +
   188  			"queued by the runtime for execution. Subtract from /gc/cleanups/executed:cleanups " +
   189  			"to approximate cleanup queue length. Useful for detecting slow cleanups holding up the queue.",
   190  		Kind:       KindUint64,
   191  		Cumulative: true,
   192  	},
   193  	{
   194  		Name:        "/gc/cycles/automatic:gc-cycles",
   195  		Description: "Count of completed GC cycles generated by the Go runtime.",
   196  		Kind:        KindUint64,
   197  		Cumulative:  true,
   198  	},
   199  	{
   200  		Name:        "/gc/cycles/forced:gc-cycles",
   201  		Description: "Count of completed GC cycles forced by the application.",
   202  		Kind:        KindUint64,
   203  		Cumulative:  true,
   204  	},
   205  	{
   206  		Name:        "/gc/cycles/total:gc-cycles",
   207  		Description: "Count of all completed GC cycles.",
   208  		Kind:        KindUint64,
   209  		Cumulative:  true,
   210  	},
   211  	{
   212  		Name: "/gc/finalizers/executed:finalizers",
   213  		Description: "Total count of finalizer functions (created by runtime.SetFinalizer) " +
   214  			"executed by the runtime. Subtract /gc/finalizers/queued:finalizers to approximate " +
   215  			"finalizer queue length. Useful for detecting finalizers overwhelming the queue, " +
   216  			"either by being too slow, or by there being too many of them.",
   217  		Kind:       KindUint64,
   218  		Cumulative: true,
   219  	},
   220  	{
   221  		Name: "/gc/finalizers/queued:finalizers",
   222  		Description: "Total count of finalizer functions (created by runtime.SetFinalizer) and " +
   223  			"queued by the runtime for execution. Subtract from /gc/finalizers/executed:finalizers " +
   224  			"to approximate finalizer queue length. Useful for detecting slow finalizers holding up the queue.",
   225  		Kind:       KindUint64,
   226  		Cumulative: true,
   227  	},
   228  	{
   229  		Name: "/gc/gogc:percent",
   230  		Description: "Heap size target percentage configured by the user, otherwise 100. This " +
   231  			"value is set by the GOGC environment variable, and the runtime/debug.SetGCPercent " +
   232  			"function.",
   233  		Kind: KindUint64,
   234  	},
   235  	{
   236  		Name: "/gc/gomemlimit:bytes",
   237  		Description: "Go runtime memory limit configured by the user, otherwise " +
   238  			"math.MaxInt64. This value is set by the GOMEMLIMIT environment variable, and " +
   239  			"the runtime/debug.SetMemoryLimit function.",
   240  		Kind: KindUint64,
   241  	},
   242  	{
   243  		Name: "/gc/heap/allocs-by-size:bytes",
   244  		Description: "Distribution of heap allocations by approximate size. " +
   245  			"Bucket counts increase monotonically. " +
   246  			"Note that this does not include tiny objects as defined by " +
   247  			"/gc/heap/tiny/allocs:objects, only tiny blocks.",
   248  		Kind:       KindFloat64Histogram,
   249  		Cumulative: true,
   250  	},
   251  	{
   252  		Name:        "/gc/heap/allocs:bytes",
   253  		Description: "Cumulative sum of memory allocated to the heap by the application.",
   254  		Kind:        KindUint64,
   255  		Cumulative:  true,
   256  	},
   257  	{
   258  		Name: "/gc/heap/allocs:objects",
   259  		Description: "Cumulative count of heap allocations triggered by the application. " +
   260  			"Note that this does not include tiny objects as defined by " +
   261  			"/gc/heap/tiny/allocs:objects, only tiny blocks.",
   262  		Kind:       KindUint64,
   263  		Cumulative: true,
   264  	},
   265  	{
   266  		Name: "/gc/heap/frees-by-size:bytes",
   267  		Description: "Distribution of freed heap allocations by approximate size. " +
   268  			"Bucket counts increase monotonically. " +
   269  			"Note that this does not include tiny objects as defined by " +
   270  			"/gc/heap/tiny/allocs:objects, only tiny blocks.",
   271  		Kind:       KindFloat64Histogram,
   272  		Cumulative: true,
   273  	},
   274  	{
   275  		Name:        "/gc/heap/frees:bytes",
   276  		Description: "Cumulative sum of heap memory freed by the garbage collector.",
   277  		Kind:        KindUint64,
   278  		Cumulative:  true,
   279  	},
   280  	{
   281  		Name: "/gc/heap/frees:objects",
   282  		Description: "Cumulative count of heap allocations whose storage was freed " +
   283  			"by the garbage collector. " +
   284  			"Note that this does not include tiny objects as defined by " +
   285  			"/gc/heap/tiny/allocs:objects, only tiny blocks.",
   286  		Kind:       KindUint64,
   287  		Cumulative: true,
   288  	},
   289  	{
   290  		Name:        "/gc/heap/goal:bytes",
   291  		Description: "Heap size target for the end of the GC cycle.",
   292  		Kind:        KindUint64,
   293  	},
   294  	{
   295  		Name:        "/gc/heap/live:bytes",
   296  		Description: "Heap memory occupied by live objects that were marked by the previous GC.",
   297  		Kind:        KindUint64,
   298  	},
   299  	{
   300  		Name:        "/gc/heap/objects:objects",
   301  		Description: "Number of objects, live or unswept, occupying heap memory.",
   302  		Kind:        KindUint64,
   303  	},
   304  	{
   305  		Name: "/gc/heap/tiny/allocs:objects",
   306  		Description: "Count of small allocations that are packed together into blocks. " +
   307  			"These allocations are counted separately from other allocations " +
   308  			"because each individual allocation is not tracked by the runtime, " +
   309  			"only their block. Each block is already accounted for in " +
   310  			"allocs-by-size and frees-by-size.",
   311  		Kind:       KindUint64,
   312  		Cumulative: true,
   313  	},
   314  	{
   315  		Name: "/gc/limiter/last-enabled:gc-cycle",
   316  		Description: "GC cycle the last time the GC CPU limiter was enabled. " +
   317  			"This metric is useful for diagnosing the root cause of an out-of-memory " +
   318  			"error, because the limiter trades memory for CPU time when the GC's CPU " +
   319  			"time gets too high. This is most likely to occur with use of SetMemoryLimit. " +
   320  			"The first GC cycle is cycle 1, so a value of 0 indicates that it was never enabled.",
   321  		Kind: KindUint64,
   322  	},
   323  	{
   324  		Name:        "/gc/pauses:seconds",
   325  		Description: "Deprecated. Prefer the identical /sched/pauses/total/gc:seconds.",
   326  		Kind:        KindFloat64Histogram,
   327  		Cumulative:  true,
   328  	},
   329  	{
   330  		Name:        "/gc/scan/globals:bytes",
   331  		Description: "The total amount of global variable space that is scannable.",
   332  		Kind:        KindUint64,
   333  	},
   334  	{
   335  		Name:        "/gc/scan/heap:bytes",
   336  		Description: "The total amount of heap space that is scannable.",
   337  		Kind:        KindUint64,
   338  	},
   339  	{
   340  		Name:        "/gc/scan/stack:bytes",
   341  		Description: "The number of bytes of stack that were scanned last GC cycle.",
   342  		Kind:        KindUint64,
   343  	},
   344  	{
   345  		Name:        "/gc/scan/total:bytes",
   346  		Description: "The total amount space that is scannable. Sum of all metrics in /gc/scan.",
   347  		Kind:        KindUint64,
   348  	},
   349  	{
   350  		Name:        "/gc/stack/starting-size:bytes",
   351  		Description: "The stack size of new goroutines.",
   352  		Kind:        KindUint64,
   353  		Cumulative:  false,
   354  	},
   355  	{
   356  		Name: "/memory/classes/heap/free:bytes",
   357  		Description: "Memory that is completely free and eligible to be returned to the underlying system, " +
   358  			"but has not been. This metric is the runtime's estimate of free address space that is backed by " +
   359  			"physical memory.",
   360  		Kind: KindUint64,
   361  	},
   362  	{
   363  		Name:        "/memory/classes/heap/objects:bytes",
   364  		Description: "Memory occupied by live objects and dead objects that have not yet been marked free by the garbage collector.",
   365  		Kind:        KindUint64,
   366  	},
   367  	{
   368  		Name: "/memory/classes/heap/released:bytes",
   369  		Description: "Memory that is completely free and has been returned to the underlying system. This " +
   370  			"metric is the runtime's estimate of free address space that is still mapped into the process, " +
   371  			"but is not backed by physical memory.",
   372  		Kind: KindUint64,
   373  	},
   374  	{
   375  		Name: "/memory/classes/heap/stacks:bytes",
   376  		Description: "Memory allocated from the heap that is reserved for stack space, whether or not it is currently in-use. " +
   377  			"Currently, this represents all stack memory for goroutines. It also includes all OS thread stacks in non-cgo programs. " +
   378  			"Note that stacks may be allocated differently in the future, and this may change.",
   379  		Kind: KindUint64,
   380  	},
   381  	{
   382  		Name:        "/memory/classes/heap/unused:bytes",
   383  		Description: "Memory that is reserved for heap objects but is not currently used to hold heap objects.",
   384  		Kind:        KindUint64,
   385  	},
   386  	{
   387  		Name:        "/memory/classes/metadata/mcache/free:bytes",
   388  		Description: "Memory that is reserved for runtime mcache structures, but not in-use.",
   389  		Kind:        KindUint64,
   390  	},
   391  	{
   392  		Name:        "/memory/classes/metadata/mcache/inuse:bytes",
   393  		Description: "Memory that is occupied by runtime mcache structures that are currently being used.",
   394  		Kind:        KindUint64,
   395  	},
   396  	{
   397  		Name:        "/memory/classes/metadata/mspan/free:bytes",
   398  		Description: "Memory that is reserved for runtime mspan structures, but not in-use.",
   399  		Kind:        KindUint64,
   400  	},
   401  	{
   402  		Name:        "/memory/classes/metadata/mspan/inuse:bytes",
   403  		Description: "Memory that is occupied by runtime mspan structures that are currently being used.",
   404  		Kind:        KindUint64,
   405  	},
   406  	{
   407  		Name:        "/memory/classes/metadata/other:bytes",
   408  		Description: "Memory that is reserved for or used to hold runtime metadata.",
   409  		Kind:        KindUint64,
   410  	},
   411  	{
   412  		Name: "/memory/classes/os-stacks:bytes",
   413  		Description: "Stack memory allocated by the underlying operating system. " +
   414  			"In non-cgo programs this metric is currently zero. This may change in the future." +
   415  			"In cgo programs this metric includes OS thread stacks allocated directly from the OS. " +
   416  			"Currently, this only accounts for one stack in c-shared and c-archive build modes, " +
   417  			"and other sources of stacks from the OS are not measured. This too may change in the future.",
   418  		Kind: KindUint64,
   419  	},
   420  	{
   421  		Name:        "/memory/classes/other:bytes",
   422  		Description: "Memory used by execution trace buffers, structures for debugging the runtime, finalizer and profiler specials, and more.",
   423  		Kind:        KindUint64,
   424  	},
   425  	{
   426  		Name:        "/memory/classes/profiling/buckets:bytes",
   427  		Description: "Memory that is used by the stack trace hash map used for profiling.",
   428  		Kind:        KindUint64,
   429  	},
   430  	{
   431  		Name:        "/memory/classes/total:bytes",
   432  		Description: "All memory mapped by the Go runtime into the current process as read-write. Note that this does not include memory mapped by code called via cgo or via the syscall package. Sum of all metrics in /memory/classes.",
   433  		Kind:        KindUint64,
   434  	},
   435  	{
   436  		Name:        "/sched/gomaxprocs:threads",
   437  		Description: "The current runtime.GOMAXPROCS setting, or the number of operating system threads that can execute user-level Go code simultaneously.",
   438  		Kind:        KindUint64,
   439  	},
   440  	{
   441  		Name:        "/sched/goroutines:goroutines",
   442  		Description: "Count of live goroutines.",
   443  		Kind:        KindUint64,
   444  	},
   445  	{
   446  		Name:        "/sched/latencies:seconds",
   447  		Description: "Distribution of the time goroutines have spent in the scheduler in a runnable state before actually running. Bucket counts increase monotonically.",
   448  		Kind:        KindFloat64Histogram,
   449  		Cumulative:  true,
   450  	},
   451  	{
   452  		Name:        "/sched/pauses/stopping/gc:seconds",
   453  		Description: "Distribution of individual GC-related stop-the-world stopping latencies. This is the time it takes from deciding to stop the world until all Ps are stopped. This is a subset of the total GC-related stop-the-world time (/sched/pauses/total/gc:seconds). During this time, some threads may be executing. Bucket counts increase monotonically.",
   454  		Kind:        KindFloat64Histogram,
   455  		Cumulative:  true,
   456  	},
   457  	{
   458  		Name:        "/sched/pauses/stopping/other:seconds",
   459  		Description: "Distribution of individual non-GC-related stop-the-world stopping latencies. This is the time it takes from deciding to stop the world until all Ps are stopped. This is a subset of the total non-GC-related stop-the-world time (/sched/pauses/total/other:seconds). During this time, some threads may be executing. Bucket counts increase monotonically.",
   460  		Kind:        KindFloat64Histogram,
   461  		Cumulative:  true,
   462  	},
   463  	{
   464  		Name:        "/sched/pauses/total/gc:seconds",
   465  		Description: "Distribution of individual GC-related stop-the-world pause latencies. This is the time from deciding to stop the world until the world is started again. Some of this time is spent getting all threads to stop (this is measured directly in /sched/pauses/stopping/gc:seconds), during which some threads may still be running. Bucket counts increase monotonically.",
   466  		Kind:        KindFloat64Histogram,
   467  		Cumulative:  true,
   468  	},
   469  	{
   470  		Name:        "/sched/pauses/total/other:seconds",
   471  		Description: "Distribution of individual non-GC-related stop-the-world pause latencies. This is the time from deciding to stop the world until the world is started again. Some of this time is spent getting all threads to stop (measured directly in /sched/pauses/stopping/other:seconds). Bucket counts increase monotonically.",
   472  		Kind:        KindFloat64Histogram,
   473  		Cumulative:  true,
   474  	},
   475  	{
   476  		Name:        "/sync/mutex/wait/total:seconds",
   477  		Description: "Approximate cumulative time goroutines have spent blocked on a sync.Mutex, sync.RWMutex, or runtime-internal lock. This metric is useful for identifying global changes in lock contention. Collect a mutex or block profile using the runtime/pprof package for more detailed contention data.",
   478  		Kind:        KindFloat64,
   479  		Cumulative:  true,
   480  	},
   481  }
   482  
   483  func init() {
   484  	// Insert all the non-default-reporting GODEBUGs into the table,
   485  	// preserving the overall sort order.
   486  	i := 0
   487  	for i < len(allDesc) && allDesc[i].Name < "/godebug/" {
   488  		i++
   489  	}
   490  	more := make([]Description, i, len(allDesc)+len(godebugs.All))
   491  	copy(more, allDesc)
   492  	for _, info := range godebugs.All {
   493  		if !info.Opaque {
   494  			more = append(more, Description{
   495  				Name: "/godebug/non-default-behavior/" + info.Name + ":events",
   496  				Description: "The number of non-default behaviors executed by the " +
   497  					info.Package + " package " + "due to a non-default " +
   498  					"GODEBUG=" + info.Name + "=... setting.",
   499  				Kind:       KindUint64,
   500  				Cumulative: true,
   501  			})
   502  		}
   503  	}
   504  	allDesc = append(more, allDesc[i:]...)
   505  }
   506  
   507  // All returns a slice of containing metric descriptions for all supported metrics.
   508  func All() []Description {
   509  	return allDesc
   510  }
   511
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