Add pressure stall information (PSI) meters on Linux

The pressure stall information (PSI) metrics provide useful information on delays caused by waiting for CPU, IO and memory. Particularly on busy servers it can provide a quick overview of what's "slowing things down". This feature is supported on Linux >= 4.20. The interface is documented here: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/plain/Documentation/accounting/psi.txt These links provide rationale: https://lwn.net/Articles/759781/ https://facebookmicrosites.github.io/psi/ The following metrics are added, corresponding to the currently exposed lines (see `head /proc/pressure/*`): - PressureStallCPUSome - PressureStallIOSome - PressureStallIOFull - PressureStallMemorySome - PressureStallMemoryFull The color scheme is the same as that used for Load Average, however I gave it separate entries just in case someone wants to change them specifically. Tested on 4.20.7-arch1-1-ARCH, on the linux platform. Also tested that other platforms still compile (changed configure to use the unsupported platform). Closes #879.
2025-07-12 12:14:36 +03:00 · 2019-02-11 20:04:12 +02:00
parent 402e46bb82
commit 08feb8585b
7 changed files with 212 additions and 2 deletions
--- a/linux/PressureStallMeter.c
+++ b/linux/PressureStallMeter.c
@ -0,0 +1,133 @@
+/*
+htop - PressureStallMeter.c
+(C) 2004-2011 Hisham H. Muhammad
+(C) 2019 Ran Benita
+Released under the GNU GPL, see the COPYING file
+in the source distribution for its full text.
+*/
+
+#include "PressureStallMeter.h"
+#include "Platform.h"
+#include "CRT.h"
+
+#include <string.h>
+
+/*{
+#include "Meter.h"
+}*/
+
+static int PressureStallMeter_attributes[] = {
+   PRESSURE_STALL_TEN, PRESSURE_STALL_SIXTY, PRESSURE_STALL_THREEHUNDRED
+};
+
+static void PressureStallMeter_updateValues(Meter* this, char* buffer, int len) {
+    const char *file;
+    if (strstr(Meter_name(this), "CPU")) {
+       file = "cpu";
+    } else if (strstr(Meter_name(this), "IO")) {
+       file = "io";
+    } else {
+       file = "memory";
+    }
+
+    bool some;
+    if (strstr(Meter_name(this), "Some")) {
+       some = true;
+    } else {
+       some = false;
+    }
+
+    Platform_getPressureStall(file, some, &this->values[0], &this->values[1], &this->values[2]);
+    xSnprintf(buffer, len, "xxxx %.2lf%% %.2lf%% %.2lf%%", this->values[0], this->values[1], this->values[2]);
+}
+
+static void PressureStallMeter_display(Object* cast, RichString* out) {
+   Meter* this = (Meter*)cast;
+   char buffer[20];
+   xSnprintf(buffer, sizeof(buffer), "%.2lf%% ", this->values[0]);
+   RichString_write(out, CRT_colors[PRESSURE_STALL_TEN], buffer);
+   xSnprintf(buffer, sizeof(buffer), "%.2lf%% ", this->values[1]);
+   RichString_append(out, CRT_colors[PRESSURE_STALL_SIXTY], buffer);
+   xSnprintf(buffer, sizeof(buffer), "%.2lf%% ", this->values[2]);
+   RichString_append(out, CRT_colors[PRESSURE_STALL_THREEHUNDRED], buffer);
+}
+
+MeterClass PressureStallCPUSomeMeter_class = {
+   .super = {
+      .extends = Class(Meter),
+      .delete = Meter_delete,
+      .display = PressureStallMeter_display,
+   },
+   .updateValues = PressureStallMeter_updateValues,
+   .defaultMode = TEXT_METERMODE,
+   .maxItems = 3,
+   .total = 100.0,
+   .attributes = PressureStallMeter_attributes,
+   .name = "PressureStallCPUSome",
+   .uiName = "Pressure Stall Information, some CPU",
+   .caption = "Some CPU pressure: "
+};
+
+MeterClass PressureStallIOSomeMeter_class = {
+   .super = {
+      .extends = Class(Meter),
+      .delete = Meter_delete,
+      .display = PressureStallMeter_display,
+   },
+   .updateValues = PressureStallMeter_updateValues,
+   .defaultMode = TEXT_METERMODE,
+   .maxItems = 3,
+   .total = 100.0,
+   .attributes = PressureStallMeter_attributes,
+   .name = "PressureStallIOSome",
+   .uiName = "Pressure Stall Information, some IO",
+   .caption = "Some IO  pressure: "
+};
+
+MeterClass PressureStallIOFullMeter_class = {
+   .super = {
+      .extends = Class(Meter),
+      .delete = Meter_delete,
+      .display = PressureStallMeter_display,
+   },
+   .updateValues = PressureStallMeter_updateValues,
+   .defaultMode = TEXT_METERMODE,
+   .maxItems = 3,
+   .total = 100.0,
+   .attributes = PressureStallMeter_attributes,
+   .name = "PressureStallIOFull",
+   .uiName = "Pressure Stall Information, full IO",
+   .caption = "Full IO  pressure: "
+};
+
+MeterClass PressureStallMemorySomeMeter_class = {
+   .super = {
+      .extends = Class(Meter),
+      .delete = Meter_delete,
+      .display = PressureStallMeter_display,
+   },
+   .updateValues = PressureStallMeter_updateValues,
+   .defaultMode = TEXT_METERMODE,
+   .maxItems = 3,
+   .total = 100.0,
+   .attributes = PressureStallMeter_attributes,
+   .name = "PressureStallMemorySome",
+   .uiName = "Pressure Stall Information, some memory",
+   .caption = "Some Mem pressure: "
+};
+
+MeterClass PressureStallMemoryFullMeter_class = {
+   .super = {
+      .extends = Class(Meter),
+      .delete = Meter_delete,
+      .display = PressureStallMeter_display,
+   },
+   .updateValues = PressureStallMeter_updateValues,
+   .defaultMode = TEXT_METERMODE,
+   .maxItems = 3,
+   .total = 100.0,
+   .attributes = PressureStallMeter_attributes,
+   .name = "PressureStallMemoryFull",
+   .uiName = "Pressure Stall Information, full memory",
+   .caption = "Full Mem pressure: "
+};