32a7757a03
irqbalance has been broken for a long time. Its ability to properly detect msi irqs and to correctly identify interrupt types (net vs. storage vs. other, etc), has been based on some tenuous string comparison logic that was easily broken by administrative name changes for interfaces. I've recently submitted this patch: https://lkml.org/lkml/2011/9/19/176 Which lets us use sysfs exclusively for finding device interrupts, which in turns lets us definitavely identify irq types (legacy pci vs. msi), as well as properly classifying them using the pci device class value. Additionally, this patch rips out the code that attemtps to bias interrupt count volumes using network statistics, since theres no sane way to be certain a single network interrupt is responsible for the number of packets received on a given interface. Workload computation is now done on soley on irq count. This may change in the future, adding /proc/stat irq and softirq time to the biasing mechanism. Note that without the above kernel change, this doesn't work right. Irqbalance contains a self check in which it identifies MSI interrupts in /proc/interrupts still. If it sees MSI irqs in /proc/interrupts, but none in sysfs, then it will issue a loud warning about irqs being missclassified until the kernel is updated. Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
116 lines
2.8 KiB
C
116 lines
2.8 KiB
C
/*
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* Copyright (C) 2006, Intel Corporation
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*
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* This file is part of irqbalance
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*
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* This program file is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
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* for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program in a file named COPYING; if not, write to the
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* Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor,
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* Boston, MA 02110-1301 USA
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*/
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#include "config.h"
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#include <stdio.h>
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#include <stdlib.h>
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#include <unistd.h>
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#include <stdint.h>
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#include <string.h>
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#include <syslog.h>
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#include "cpumask.h"
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#include "irqbalance.h"
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#define LINESIZE 4096
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static int proc_int_has_msi = 0;
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static int msi_found_in_sysfs = 0;
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void parse_proc_interrupts(void)
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{
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FILE *file;
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char *line = NULL;
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size_t size = 0;
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int int_type;
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file = fopen("/proc/interrupts", "r");
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if (!file)
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return;
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/* first line is the header we don't need; nuke it */
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if (getline(&line, &size, file)==0) {
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free(line);
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return;
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}
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while (!feof(file)) {
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int cpunr;
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int number;
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uint64_t count;
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char *c, *c2;
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if (getline(&line, &size, file)==0)
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break;
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if (!proc_int_has_msi)
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if (strstr(line, "MSI") != NULL)
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proc_int_has_msi = 1;
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/* lines with letters in front are special, like NMI count. Ignore */
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if (!(line[0]==' ' || (line[0]>='0' && line[0]<='9')))
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break;
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c = strchr(line, ':');
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if (!c)
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continue;
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*c = 0;
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c++;
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number = strtoul(line, NULL, 10);
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count = 0;
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cpunr = 0;
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c2=NULL;
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while (1) {
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uint64_t C;
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C = strtoull(c, &c2, 10);
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if (c==c2) /* end of numbers */
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break;
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count += C;
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c=c2;
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cpunr++;
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}
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if (cpunr != core_count)
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need_cpu_rescan = 1;
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set_interrupt_count(number, count);
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/* is interrupt MSI based? */
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int_type = find_irq_integer_prop(number, IRQ_TYPE);
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if ((int_type == IRQ_TYPE_MSI) || (int_type == IRQ_TYPE_MSIX)) {
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msi_found_in_sysfs = 1;
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/* Set numa node for irq if it was MSI */
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if (debug_mode)
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printf("Set MSI interrupt for %d\n", number);
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set_msi_interrupt_numa(number, c);
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}
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}
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if ((proc_int_has_msi) && (!msi_found_in_sysfs)) {
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syslog(LOG_WARNING, "WARNING: MSI interrupts found in /proc/interrupts\n");
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syslog(LOG_WARNING, "But none found in sysfs, you need to update your kernel\n");
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syslog(LOG_WARNING, "Until then, IRQs will be improperly classified\n");
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/*
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* Set msi_foun_in_sysfs, so we don't get this error constantly
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*/
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msi_found_in_sysfs = 1;
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}
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fclose(file);
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free(line);
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}
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