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ProcessList: cleanup the tree set sorting remains

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They're no longer needed as rebuilding the tree from scratch is just as
fast.
This commit is contained in:
Denis Lisov 2022-01-07 21:05:43 +03:00 committed by BenBE
parent fa3e0d06c2
commit 82d34deaf1
3 changed files with 4 additions and 181 deletions
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3
Process.h
View File

@ -250,10 +250,7 @@ typedef struct Process_ {
* Internal state for tree-mode.
*/
int indent;
unsigned int tree_left;
unsigned int tree_right;
unsigned int tree_depth;
unsigned int tree_index;
/* Has no known parent process */
bool isRoot;

180
ProcessList.c
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@ -25,8 +25,6 @@ ProcessList* ProcessList_init(ProcessList* this, const ObjectClass* klass, Users
this->displayList = Vector_new(klass, false, DEFAULT_SIZE);
this->processTable = Hashtable_new(200, false);
this->displayTreeSet = Hashtable_new(200, false);
this->draftingTreeSet = Hashtable_new(200, false);
this->needsSort = true;
this->usersTable = usersTable;
@ -74,8 +72,6 @@ void ProcessList_done(ProcessList* this) {
}
#endif
Hashtable_delete(this->draftingTreeSet);
Hashtable_delete(this->displayTreeSet);
Hashtable_delete(this->processTable);
Vector_delete(this->displayList);
@ -195,144 +191,7 @@ void ProcessList_remove(ProcessList* this, const Process* p) {
assert(Hashtable_count(this->processTable) == Vector_count(this->processes));
}
// ProcessList_updateTreeSetLayer sorts this->displayTreeSet,
// relying only on itself.
//
// Algorithm
//
// The algorithm is based on `depth-first search`,
// even though `breadth-first search` approach may be more efficient on first glance,
// after comparison it may be not, as it's not safe to go deeper without first updating the tree structure.
// If it would be safe that approach would likely bring an advantage in performance.
//
// Each call of the function looks for a 'layer'. A 'layer' is a list of processes with the same depth.
// First it sorts a list. Then it runs the function recursively for each element of the sorted list.
// After that it updates the settings of processes.
//
// It relies on `leftBound` and `rightBound` as an optimization to cut the list size at the time it builds a 'layer'.
//
// It uses a temporary Hashtable `draftingTreeSet` because it's not safe to traverse a tree
// and at the same time make changes in it.
//
static void ProcessList_updateTreeSetLayer(ProcessList* this, unsigned int leftBound, unsigned int rightBound, unsigned int deep, unsigned int left, unsigned int right, unsigned int* index, unsigned int* treeIndex, int indent) {
// It's guaranteed that layer_size is enough space
// but most likely it needs less. Specifically on first iteration.
int layerSize = (right - left) / 2;
// check if we reach `children` of `leaves`
if (layerSize == 0)
return;
Vector* layer = Vector_new(Vector_type(this->displayList), false, layerSize);
// Find all processes on the same layer (process with the same `deep` value
// and included in a range from `leftBound` to `rightBound`).
//
// This loop also keeps track of left_bound and right_bound of these processes
// in order not to lose this information once the list is sorted.
//
// The variables left_bound and right_bound are different from what the values lhs and rhs represent.
// While left_bound and right_bound define a range of processes to look at, the values given by lhs and rhs are indices into an array
//
// In the below example note how filtering a range of indices i is different from filtering for processes in the bounds left_bound < x < right_bound …
//
// The nested tree set is sorted by left value, which is guaranteed upon entry/exit of this function.
//
// i | l | r
// 1 | 1 | 9
// 2 | 2 | 8
// 3 | 4 | 5
// 4 | 6 | 7
for (unsigned int i = leftBound; i < rightBound; i++) {
Process* proc = (Process*)Hashtable_get(this->displayTreeSet, i);
assert(proc);
if (proc && proc->tree_depth == deep && proc->tree_left > left && proc->tree_right < right) {
if (Vector_size(layer) > 0) {
Process* previous_process = (Process*)Vector_get(layer, Vector_size(layer) - 1);
// Make a 'right_bound' of previous_process in a layer the current process's index.
//
// Use 'tree_depth' as a temporal variable.
// It's safe to do as later 'tree_depth' will be renovated.
previous_process->tree_depth = proc->tree_index;
}
Vector_add(layer, proc);
}
}
// The loop above changes just up to process-1.
// So the last process of the layer isn't updated by the above code.
//
// Thus, if present, set the `rightBound` to the last process on the layer
if (Vector_size(layer) > 0) {
Process* previous_process = (Process*)Vector_get(layer, Vector_size(layer) - 1);
previous_process->tree_depth = rightBound;
}
Vector_quickSort(layer);
int size = Vector_size(layer);
for (int i = 0; i < size; i++) {
Process* proc = (Process*)Vector_get(layer, i);
unsigned int idx = (*index)++;
int newLeft = (*treeIndex)++;
int level = deep == 0 ? 0 : (int)deep - 1;
int currentIndent = indent == -1 ? 0 : indent | (1 << level);
int nextIndent = indent == -1 ? 0 : ((i < size - 1) ? currentIndent : indent);
unsigned int newLeftBound = proc->tree_index;
unsigned int newRightBound = proc->tree_depth;
ProcessList_updateTreeSetLayer(this, newLeftBound, newRightBound, deep + 1, proc->tree_left, proc->tree_right, index, treeIndex, nextIndent);
int newRight = (*treeIndex)++;
proc->tree_left = newLeft;
proc->tree_right = newRight;
proc->tree_index = idx;
proc->tree_depth = deep;
if (indent == -1) {
proc->indent = 0;
} else if (i == size - 1) {
proc->indent = -currentIndent;
} else {
proc->indent = currentIndent;
}
Hashtable_put(this->draftingTreeSet, proc->tree_index, proc);
// It's not strictly necessary to do this, but doing so anyways
// allows for checking the correctness of the inner workings.
Hashtable_remove(this->displayTreeSet, newLeftBound);
}
Vector_delete(layer);
}
static void ProcessList_updateTreeSet(ProcessList* this) {
unsigned int index = 0;
unsigned int tree_index = 1;
const int vsize = Vector_size(this->displayList);
assert(Hashtable_count(this->draftingTreeSet) == 0);
assert((int)Hashtable_count(this->displayTreeSet) == vsize);
ProcessList_updateTreeSetLayer(this, 0, vsize, 0, 0, vsize * 2 + 1, &index, &tree_index, -1);
Hashtable* tmp = this->draftingTreeSet;
this->draftingTreeSet = this->displayTreeSet;
this->displayTreeSet = tmp;
assert(Hashtable_count(this->draftingTreeSet) == 0);
assert((int)Hashtable_count(this->displayTreeSet) == vsize);
}
static void ProcessList_buildTreeBranch(ProcessList* this, pid_t pid, int level, int indent, bool show, int* node_counter, int* node_index) {
static void ProcessList_buildTreeBranch(ProcessList* this, pid_t pid, int level, int indent, bool show) {
// On OpenBSD the kernel thread 'swapper' has pid 0.
// Do not treat it as root of any tree.
if (pid == 0)
@ -366,10 +225,6 @@ static void ProcessList_buildTreeBranch(ProcessList* this, pid_t pid, int level,
for (int i = l; i < r; i++) {
Process* process = (Process*)Vector_get(this->processes, i);
int index = (*node_index)++;
int lft = (*node_counter)++;
if (!show) {
process->show = false;
}
@ -380,30 +235,17 @@ static void ProcessList_buildTreeBranch(ProcessList* this, pid_t pid, int level,
assert(Vector_size(this->displayList) == s + 1); (void)s;
int nextIndent = indent | (1 << level);
ProcessList_buildTreeBranch(this, process->pid, level + 1, (i < lastShown) ? nextIndent : indent, process->show && process->showChildren, node_counter, node_index);
ProcessList_buildTreeBranch(this, process->pid, level + 1, (i < lastShown) ? nextIndent : indent, process->show && process->showChildren);
if (i == lastShown) {
process->indent = -nextIndent;
} else {
process->indent = nextIndent;
}
int rht = (*node_counter)++;
process->tree_left = lft;
process->tree_right = rht;
process->tree_depth = level + 1;
process->tree_index = index;
Hashtable_put(this->displayTreeSet, index, process);
}
}
static int ProcessList_treeProcessCompare(const void* v1, const void* v2) {
const Process* p1 = (const Process*)v1;
const Process* p2 = (const Process*)v2;
return SPACESHIP_NUMBER(p1->tree_left, p2->tree_left);
}
static int compareProcessByKnownParentThenNatural(const void* v1, const void* v2) {
const Process* p1 = (const Process*)v1;
const Process* p2 = (const Process*)v2;
@ -423,9 +265,6 @@ static int compareProcessByKnownParentThenNatural(const void* v1, const void* v2
static void ProcessList_buildTree(ProcessList* this) {
Vector_prune(this->displayList);
int node_counter = 1;
int node_index = 0;
// Mark root processes
int vsize = Vector_size(this->processes);
for (int i = 0; i < vsize; i++) {
@ -460,12 +299,8 @@ static void ProcessList_buildTree(ProcessList* this) {
process = (Process*)Vector_get(this->processes, i);
process->indent = 0;
process->tree_depth = 0;
process->tree_left = node_counter++;
process->tree_index = node_index++;
Vector_add(this->displayList, process);
Hashtable_put(this->displayTreeSet, process->tree_index, process);
ProcessList_buildTreeBranch(this, process->pid, 0, 0, process->showChildren, &node_counter, &node_index);
process->tree_right = node_counter++;
ProcessList_buildTreeBranch(this, process->pid, 0, 0, process->showChildren);
continue;
}
}
@ -658,13 +493,6 @@ void ProcessList_scan(ProcessList* this, bool pauseProcessUpdate) {
// Set UID column width based on max UID.
Process_setUidColumnWidth(maxUid);
if (this->settings->ss->treeView) {
// Clear out the hashtable to avoid any left-over processes from previous build
//
// The sorting algorithm relies on the fact that
// len(this->displayTreeSet) == len(this->processes)
Hashtable_clear(this->displayTreeSet);
if (this->settings->ss->treeView)
ProcessList_buildTree(this);
}
}

2
ProcessList.h
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@ -48,8 +48,6 @@ typedef struct ProcessList_ {
Hashtable* processTable; /* fast known process lookup by PID */
UsersTable* usersTable;
Hashtable* displayTreeSet;
Hashtable* draftingTreeSet;
bool needsSort;
Hashtable* dynamicMeters; /* runtime-discovered meters */