From: Ming Lei <ming.lei@redhat.com>
To: Long Li <longli@microsoft.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Keith Busch <keith.busch@intel.com>, Jens Axboe <axboe@fb.com>,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
John Garry <john.garry@huawei.com>,
Hannes Reinecke <hare@suse.com>,
"linux-nvme@lists.infradead.org" <linux-nvme@lists.infradead.org>,
"linux-scsi@vger.kernel.org" <linux-scsi@vger.kernel.org>
Subject: Re: [PATCH 1/4] softirq: implement IRQ flood detection mechanism
Date: Fri, 30 Aug 2019 08:55:01 +0800 [thread overview]
Message-ID: <20190830005459.GB25999@ming.t460p> (raw)
In-Reply-To: <DM5PR21MB0748278B86FB5103AF6E8A37CEA20@DM5PR21MB0748.namprd21.prod.outlook.com>
On Thu, Aug 29, 2019 at 06:15:00AM +0000, Long Li wrote:
> >>>For some high performance IO devices, interrupt may come very frequently,
> >>>meantime IO request completion may take a bit time. Especially on some
> >>>devices(SCSI or NVMe), IO requests can be submitted concurrently from
> >>>multiple CPU cores, however IO completion is only done on one of these
> >>>submission CPU cores.
> >>>
> >>>Then IRQ flood can be easily triggered, and CPU lockup.
> >>>
> >>>Implement one simple generic CPU IRQ flood detection mechanism. This
> >>>mechanism uses the CPU average interrupt interval to evaluate if IRQ flood
> >>>is triggered. The Exponential Weighted Moving Average(EWMA) is used to
> >>>compute CPU average interrupt interval.
> >>>
> >>>Cc: Long Li <longli@microsoft.com>
> >>>Cc: Ingo Molnar <mingo@redhat.com>,
> >>>Cc: Peter Zijlstra <peterz@infradead.org>
> >>>Cc: Keith Busch <keith.busch@intel.com>
> >>>Cc: Jens Axboe <axboe@fb.com>
> >>>Cc: Christoph Hellwig <hch@lst.de>
> >>>Cc: Sagi Grimberg <sagi@grimberg.me>
> >>>Cc: John Garry <john.garry@huawei.com>
> >>>Cc: Thomas Gleixner <tglx@linutronix.de>
> >>>Cc: Hannes Reinecke <hare@suse.com>
> >>>Cc: linux-nvme@lists.infradead.org
> >>>Cc: linux-scsi@vger.kernel.org
> >>>Signed-off-by: Ming Lei <ming.lei@redhat.com>
> >>>---
> >>> drivers/base/cpu.c | 25 ++++++++++++++++++++++
> >>> include/linux/hardirq.h | 2 ++
> >>> kernel/softirq.c | 46
> >>>+++++++++++++++++++++++++++++++++++++++++
> >>> 3 files changed, 73 insertions(+)
> >>>
> >>>diff --git a/drivers/base/cpu.c b/drivers/base/cpu.c index
> >>>cc37511de866..7277d1aa0906 100644
> >>>--- a/drivers/base/cpu.c
> >>>+++ b/drivers/base/cpu.c
> >>>@@ -20,6 +20,7 @@
> >>> #include <linux/tick.h>
> >>> #include <linux/pm_qos.h>
> >>> #include <linux/sched/isolation.h>
> >>>+#include <linux/hardirq.h>
> >>>
> >>> #include "base.h"
> >>>
> >>>@@ -183,10 +184,33 @@ static struct attribute_group
> >>>crash_note_cpu_attr_group = { }; #endif
> >>>
> >>>+static ssize_t show_irq_interval(struct device *dev,
> >>>+ struct device_attribute *attr, char *buf) {
> >>>+ struct cpu *cpu = container_of(dev, struct cpu, dev);
> >>>+ ssize_t rc;
> >>>+ int cpunum;
> >>>+
> >>>+ cpunum = cpu->dev.id;
> >>>+
> >>>+ rc = sprintf(buf, "%llu\n", irq_get_avg_interval(cpunum));
> >>>+ return rc;
> >>>+}
> >>>+
> >>>+static DEVICE_ATTR(irq_interval, 0400, show_irq_interval, NULL); static
> >>>+struct attribute *irq_interval_cpu_attrs[] = {
> >>>+ &dev_attr_irq_interval.attr,
> >>>+ NULL
> >>>+};
> >>>+static struct attribute_group irq_interval_cpu_attr_group = {
> >>>+ .attrs = irq_interval_cpu_attrs,
> >>>+};
> >>>+
> >>> static const struct attribute_group *common_cpu_attr_groups[] = { #ifdef
> >>>CONFIG_KEXEC
> >>> &crash_note_cpu_attr_group,
> >>> #endif
> >>>+ &irq_interval_cpu_attr_group,
> >>> NULL
> >>> };
> >>>
> >>>@@ -194,6 +218,7 @@ static const struct attribute_group
> >>>*hotplugable_cpu_attr_groups[] = { #ifdef CONFIG_KEXEC
> >>> &crash_note_cpu_attr_group,
> >>> #endif
> >>>+ &irq_interval_cpu_attr_group,
> >>> NULL
> >>> };
> >>>
> >>>diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h index
> >>>da0af631ded5..fd394060ddb3 100644
> >>>--- a/include/linux/hardirq.h
> >>>+++ b/include/linux/hardirq.h
> >>>@@ -8,6 +8,8 @@
> >>> #include <linux/vtime.h>
> >>> #include <asm/hardirq.h>
> >>>
> >>>+extern u64 irq_get_avg_interval(int cpu); extern bool
> >>>+irq_flood_detected(void);
> >>>
> >>> extern void synchronize_irq(unsigned int irq); extern bool
> >>>synchronize_hardirq(unsigned int irq); diff --git a/kernel/softirq.c
> >>>b/kernel/softirq.c index 0427a86743a4..96e01669a2e0 100644
> >>>--- a/kernel/softirq.c
> >>>+++ b/kernel/softirq.c
> >>>@@ -25,6 +25,7 @@
> >>> #include <linux/smpboot.h>
> >>> #include <linux/tick.h>
> >>> #include <linux/irq.h>
> >>>+#include <linux/sched/clock.h>
> >>>
> >>> #define CREATE_TRACE_POINTS
> >>> #include <trace/events/irq.h>
> >>>@@ -52,6 +53,12 @@ DEFINE_PER_CPU_ALIGNED(irq_cpustat_t, irq_stat);
> >>>EXPORT_PER_CPU_SYMBOL(irq_stat); #endif
> >>>
> >>>+struct irq_interval {
> >>>+ u64 last_irq_end;
> >>>+ u64 avg;
> >>>+};
> >>>+DEFINE_PER_CPU(struct irq_interval, avg_irq_interval);
> >>>+
> >>> static struct softirq_action softirq_vec[NR_SOFTIRQS]
> >>>__cacheline_aligned_in_smp;
> >>>
> >>> DEFINE_PER_CPU(struct task_struct *, ksoftirqd); @@ -339,6 +346,41 @@
> >>>asmlinkage __visible void do_softirq(void)
> >>> local_irq_restore(flags);
> >>> }
> >>>
> >>>+/*
> >>>+ * Update average irq interval with the Exponential Weighted Moving
> >>>+ * Average(EWMA)
> >>>+ */
> >>>+static void irq_update_interval(void)
> >>>+{
> >>>+#define IRQ_INTERVAL_EWMA_WEIGHT 128
> >>>+#define IRQ_INTERVAL_EWMA_PREV_FACTOR 127
> >>>+#define IRQ_INTERVAL_EWMA_CURR_FACTOR
> >>> (IRQ_INTERVAL_EWMA_WEIGHT - \
> >>>+ IRQ_INTERVAL_EWMA_PREV_FACTOR)
> >>>+
> >>>+ int cpu = raw_smp_processor_id();
> >>>+ struct irq_interval *inter = per_cpu_ptr(&avg_irq_interval, cpu);
> >>>+ u64 delta = sched_clock_cpu(cpu) - inter->last_irq_end;
> >>>+
> >>>+ inter->avg = (inter->avg * IRQ_INTERVAL_EWMA_PREV_FACTOR +
>
> inter->avg will start with 0? maybe use a bigger value like IRQ_FLOOD_THRESHOLD_NS
I won't be a big deal, any initial value should be fine since it is Exponential
Weighted Moving Average.
Thanks,
Ming
next prev parent reply other threads:[~2019-08-30 0:55 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-08-27 8:53 [PATCH 0/4] genirq/nvme: add IRQF_RESCUE_THREAD for avoiding IRQ flood Ming Lei
2019-08-27 8:53 ` [PATCH 1/4] softirq: implement IRQ flood detection mechanism Ming Lei
2019-08-27 14:42 ` Thomas Gleixner
2019-08-27 16:19 ` Thomas Gleixner
2019-08-27 23:04 ` Ming Lei
2019-08-27 23:12 ` Thomas Gleixner
2019-08-27 22:58 ` Ming Lei
2019-08-27 23:09 ` Thomas Gleixner
2019-08-28 11:06 ` Ming Lei
2019-08-28 11:23 ` Thomas Gleixner
2019-08-28 13:50 ` Ming Lei
2019-08-28 14:07 ` Thomas Gleixner
2019-09-03 3:30 ` Ming Lei
2019-09-03 5:59 ` Daniel Lezcano
2019-09-03 6:31 ` Ming Lei
2019-09-03 6:40 ` Daniel Lezcano
2019-09-03 7:28 ` Ming Lei
2019-09-03 7:50 ` Daniel Lezcano
2019-09-03 9:30 ` Ming Lei
2019-09-04 17:07 ` Bart Van Assche
2019-09-04 17:31 ` Daniel Lezcano
2019-09-04 17:38 ` Bart Van Assche
2019-09-04 18:02 ` Peter Zijlstra
2019-09-04 19:47 ` Bart Van Assche
2019-09-05 9:11 ` Ming Lei
2019-09-05 9:06 ` Ming Lei
2019-09-05 10:37 ` Daniel Lezcano
2019-09-06 1:22 ` Long Li
2019-09-06 4:36 ` Daniel Lezcano
2019-09-06 4:44 ` Long Li
2019-09-06 1:48 ` Ming Lei
2019-09-06 5:14 ` Daniel Lezcano
2019-09-06 18:30 ` Sagi Grimberg
2019-09-06 18:52 ` Keith Busch
2019-09-07 0:01 ` Ming Lei
2019-09-10 3:10 ` Sagi Grimberg
2019-09-18 0:00 ` Long Li
2019-09-20 17:14 ` Sagi Grimberg
2019-09-20 19:12 ` Long Li
2019-09-20 20:45 ` Sagi Grimberg
2019-09-24 0:57 ` Long Li
2019-09-18 14:37 ` Ming Lei
2019-09-20 17:09 ` Sagi Grimberg
2019-09-06 14:18 ` Keith Busch
2019-09-06 17:50 ` Long Li
2019-09-06 22:19 ` Ming Lei
2019-09-06 22:25 ` Keith Busch
2019-09-06 23:13 ` Ming Lei
2019-09-10 0:24 ` Ming Lei
2019-09-03 8:09 ` Thomas Gleixner
2019-09-03 9:24 ` Ming Lei
2019-08-29 6:15 ` Long Li
2019-08-30 0:55 ` Ming Lei [this message]
2019-08-27 8:53 ` [PATCH 2/4] genirq: add IRQF_RESCUE_THREAD Ming Lei
2019-08-27 8:53 ` [PATCH 3/4] nvme: pci: pass IRQF_RESCURE_THREAD to request_threaded_irq Ming Lei
2019-08-27 9:06 ` Johannes Thumshirn
2019-08-27 9:09 ` Ming Lei
2019-08-27 9:12 ` Johannes Thumshirn
2019-08-27 14:34 ` Keith Busch
2019-08-27 14:44 ` Keith Busch
2019-08-27 15:10 ` Bart Van Assche
2019-08-28 1:45 ` Ming Lei
2019-08-27 8:53 ` [PATCH 4/4] genirq: use irq's affinity for threaded irq with IRQF_RESCUE_THREAD Ming Lei
2019-08-27 14:35 ` Keith Busch
2019-09-06 8:50 ` John Garry
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190830005459.GB25999@ming.t460p \
--to=ming.lei@redhat.com \
--cc=axboe@fb.com \
--cc=hare@suse.com \
--cc=hch@lst.de \
--cc=john.garry@huawei.com \
--cc=keith.busch@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nvme@lists.infradead.org \
--cc=linux-scsi@vger.kernel.org \
--cc=longli@microsoft.com \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=sagi@grimberg.me \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).