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Refactor IdentifyChromeProcesses.cs
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Refactor this code to not waste time/space copying data from IProcess
to a struct. Instead, return a Dictionary indexed by IProcess (which
uniquely identifies the process, unlike PID) and grab data from IProcess
as needed. This shortens and simplifies the script.

Also rename some variables for better coding-standards compliance.
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@randomascii
randomascii committed Aug 11, 2019
1 parent 68eb47b commit 6e3f0b4
Showing 1 changed file with 31 additions and 49 deletions.
80 changes: 31 additions & 49 deletions TraceProcessors/IdentifyChromeProcesses/IdentifyChromeProcesses.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -41,56 +41,36 @@ struct CPUUsageDetails
public long contextSwitches;
}

struct ProcessSummary
// Get a dictionary of Chrome process paths, indexed by the IProcess object
// which serves as a unique identifier. Don't return a Dictionary keyed by
// PID because that will lose records whenever there is PID reuse, which is
// often.
static Dictionary<IProcess, string> GetChromePaths(IProcessDataSource processData)
{
public string imageName_;
public string exePath_;
public string commandLine_;
public uint pid_;
public uint parentPid_;

public ProcessSummary(string imageName, string exePath, string commandLine, uint pid, uint parentPid)
{
imageName_ = imageName;
exePath_ = exePath;
commandLine_ = commandLine;
pid_ = pid;
parentPid_ = parentPid;
}
}

// Get a list of Chrome processes. Most of the logic is from getting a
// a full exe path name. Don't return a Dictionary keyed by PID because
// that will lose records whenever there is PID reuse, which is often.
static List<ProcessSummary> GetProcessSummaries(IProcessDataSource processData)
{
var processSummaries = new List<ProcessSummary>();
var chromePaths = new Dictionary<IProcess, string>();

foreach (var process in processData.Processes)
{
string imageName = process.ImageName;
if (imageName != "chrome.exe")
if (process.ImageName != "chrome.exe")
continue;

uint pid = process.Id;
uint parentPid = process.ParentId;
// Extract the exePath from the command line. It is also possible to
// grab it from the process.Images.Path attribute but that sometimes
// gives weird results, is not clearly better, and makes comparing
// with the Python script more difficult.
// The exePath may or may not be quoted, and may or not have the .exe
// suffix but if we strip quotes or split on spaces it works.
string commandLine = process.CommandLine != null ? process.CommandLine : "<Unknown>";
string exe_path;
string exePath;
if (commandLine.StartsWith("\""))
exe_path = commandLine.Substring(1, commandLine.IndexOf('\"', 1) - 1);
exePath = commandLine.Substring(1, commandLine.IndexOf('\"', 1) - 1);
else
exe_path = commandLine.Split(' ')[0];
exePath = commandLine.Split(' ')[0];

processSummaries.Add(new ProcessSummary(imageName, exe_path, commandLine, pid, parentPid));
chromePaths[process] = exePath;
}

return processSummaries;
return chromePaths;
}

// Scan through a trace and print a summary of the Chrome processes, optionally with
Expand All @@ -112,7 +92,7 @@ static void ProcessTrace(ITraceProcessor trace, bool showCPUUsage, bool eventsLo
schedulingData = pendingSchedulingData.Result;

// Get a List<ProcessSummary> of all Chrome processes.
var processSummaries = GetProcessSummaries(pendingProcessData.Result);
var processSummaries = GetChromePaths(pendingProcessData.Result);

// Group all of the chrome.exe processes by browser Pid, then by type.
// pathByBrowserPid just maps from the browser Pid to the disk path to
Expand All @@ -129,20 +109,22 @@ static void ProcessTrace(ITraceProcessor trace, bool showCPUUsage, bool eventsLo
var parentPids = new Dictionary<uint, uint>();

// Dictionary of Pids and their types.
var types_by_pid = new Dictionary<uint, string>();
var typesByPid = new Dictionary<uint, string>();

// Find the space-terminated word after 'type='.
// Mark the first .* as lazy/ungreedy/reluctant so that if there are multiple
// --type options (such as with the V8 Proxy Resolver utility process) the
// first one will win. Or, at least, that's what the comments in the Python
// version of this said.
var r = new Regex(@".*? --type=(?<type>[^ ]*) .*");
foreach (var summary in processSummaries)
foreach (var entry in processSummaries)
{
if (summary.imageName_ == "chrome.exe")
var process = entry.Key;
var exePath = entry.Value;
if (process.ImageName == "chrome.exe")
{
uint pid = summary.pid_;
parentPids[pid] = summary.parentPid_;
uint pid = process.Id;
parentPids[pid] = process.ParentId;

// Look for the process type on the command-line in the
// --type= option. If no type is found then assume it is the
Expand All @@ -152,27 +134,27 @@ static void ProcessTrace(ITraceProcessor trace, bool showCPUUsage, bool eventsLo
// many ways to do this.
string type;
uint browserPid;
var match = r.Match(summary.commandLine_);
var match = r.Match(process.CommandLine);
if (match.Success)
{
type = match.Groups["type"].ToString();
if (type == "crashpad-handler")
type = "crashpad"; // Shorten the tag for better formatting
if (type == "renderer" && summary.commandLine_.Contains(" --extension-process "))
if (type == "renderer" && process.CommandLine.Contains(" --extension-process "))
{
// Extension processes are renderers with --extension-process on the command line.
type = "extension";
}
browserPid = summary.parentPid_;
browserPid = process.ParentId;
}
else
{
type = "browser";
browserPid = pid;
pathByBrowserPid[browserPid] = summary.exePath_;
pathByBrowserPid[browserPid] = exePath;
}

types_by_pid[pid] = type;
typesByPid[pid] = type;

// Retrieve or create the list of processes associated with this
// browser (parent) pid.
Expand Down Expand Up @@ -246,7 +228,7 @@ static void ProcessTrace(ITraceProcessor trace, bool showCPUUsage, bool eventsLo
}

// Map from PID to CPUUsageDetails.
var exec_times = new Dictionary<uint, CPUUsageDetails>();
var execTimes = new Dictionary<uint, CPUUsageDetails>();
if (showCPUUsage)
{
var names = new string[] { "chrome.exe", "dwm.exe", "audiodg.exe", "System", "MsMpEng.exe", "software_reporter_tool.exe" };
Expand All @@ -263,14 +245,14 @@ static void ProcessTrace(ITraceProcessor trace, bool showCPUUsage, bool eventsLo
// short this is probably faster than using a dictionary.
if (!names.Contains(slice.Process.ImageName))
continue;
exec_times.TryGetValue(slice.Process.Id, out CPUUsageDetails last);
execTimes.TryGetValue(slice.Process.Id, out CPUUsageDetails last);
last.imageName = slice.Process.ImageName;
last.ns += slice.Duration.Nanoseconds;
last.contextSwitches += 1;
exec_times[slice.Process.Id] = last;
execTimes[slice.Process.Id] = last;
}

foreach (var times in exec_times)
foreach (var times in execTimes)
{
CPUUsageDetails details = times.Value;
// Print details about other interesting processes:
Expand Down Expand Up @@ -306,7 +288,7 @@ static void ProcessTrace(ITraceProcessor trace, bool showCPUUsage, bool eventsLo
var detailsSubTotal = new CPUUsageDetails();
foreach (uint pid in type.Value)
{
exec_times.TryGetValue(pid, out CPUUsageDetails details);
execTimes.TryGetValue(pid, out CPUUsageDetails details);
detailsTotal.ns += details.ns;
detailsTotal.contextSwitches += details.contextSwitches;

Expand Down Expand Up @@ -356,7 +338,7 @@ static void ProcessTrace(ITraceProcessor trace, bool showCPUUsage, bool eventsLo
if (showCPUUsage)
{
Console.Write("\n ");
exec_times.TryGetValue(pid, out CPUUsageDetails details);
execTimes.TryGetValue(pid, out CPUUsageDetails details);
if (details.contextSwitches > 0)
Console.Write("{0,5} - {1,6} context switches, {2,8:0.00} ms CPU", pid, details.contextSwitches, details.ns / 1e6);
else
Expand Down

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