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From harish singh <harish.sing...@gmail.com>
Subject Re: airflow (1.7.0): cpu utilization reaches 70% and above
Date Mon, 13 Jun 2016 16:50:05 GMT
yup. it is the scheduler process using cpu:


The below is the usage with default out-of-box heartbeat settings.
 I will paste some numbers in something, as I play with airflow.cfg.
This is the output of `top`
  PID USER      PR  NI    VIRT    RES    SHR S  %CPU %MEM     TIME+ COMMAND
*   65 airflow   20   0  445488 112648  13308 R  61.3  0.7 834:21.23
airflow*
    1 airflow   20   0   17968   1912   1668 S   0.0  0.0   0:00.04
entrypoint.sh
   64 airflow   20   0  407972  74876  13328 S   0.0  0.5   0:01.12 airflow
  154 airflow   20   0  404404  62528   4344 S   0.0  0.4   0:00.11 airflow
  155 airflow   20   0  404404  62532   4344 S   0.0  0.4   0:00.11 airflow
  156 airflow   20   0  404404  62532   4344 S   0.0  0.4   0:00.12 airflow
  157 airflow   20   0  404404  62532   4344 S   0.0  0.4   0:00.11 airflow
  158 airflow   20   0  404404  62532   4344 S   0.0  0.4   0:00.11 airflow
  159 airflow   20   0  404404  62532   4344 S   0.0  0.4   0:00.11 airflow
  160 airflow   20   0  404404  62488   4300 S   0.0  0.4   0:00.12 airflow
  161 airflow   20   0  404404  62468   4280 S   0.0  0.4   0:00.11 airflow
  163 airflow   20   0   50356  16680   5956 S   0.0  0.1   0:08.86
gunicorn: maste
  168 airflow   20   0  457204 119940  13080 S   0.0  0.8   0:18.86
gunicorn: worke
  170 airflow   20   0  463168 126028  13080 S   0.0  0.8   0:13.81
gunicorn: worke
  171 airflow   20   0  464936 127672  13080 S   0.0  0.8   0:08.53
gunicorn: worke
  174 airflow   20   0  467460 130240  13080 S   0.0  0.8   0:08.52
gunicorn: worke
 7627 airflow   20   0   18208   3192   2672 S   0.0  0.0   0:00.04 bash
 8091 airflow   20   0   30312   7556   4784 S   0.0  0.0   0:00.00 python
28808 airflow   20   0   18208   3352   2836 S   0.0  0.0   0:00.08 bash
28822 airflow   20   0   19844   2340   2020 R   0.0  0.0   0:00.01 top


*PID 65 is the scheduler.*


airflow@80be4e775e55:~$ ps -ef
UID        PID  PPID  C STIME TTY          TIME CMD
airflow      1     0  0 Jun12 ?        00:00:00 /bin/bash ./entrypoint.sh
airflow     64     1  0 Jun12 ?        00:00:01 /usr/bin/python
/usr/local/bin/airflow webserver -p 8080
airflow     65     1 62 Jun12 ?        13:54:22 /usr/bin/python
/usr/local/bin/airflow scheduler
airflow    154    65  0 Jun12 ?        00:00:00 /usr/bin/python
/usr/local/bin/airflow scheduler
airflow    155    65  0 Jun12 ?        00:00:00 /usr/bin/python
/usr/local/bin/airflow scheduler
airflow    156    65  0 Jun12 ?        00:00:00 /usr/bin/python
/usr/local/bin/airflow scheduler
airflow    157    65  0 Jun12 ?        00:00:00 /usr/bin/python
/usr/local/bin/airflow scheduler
airflow    158    65  0 Jun12 ?        00:00:00 /usr/bin/python
/usr/local/bin/airflow scheduler
airflow    159    65  0 Jun12 ?        00:00:00 /usr/bin/python
/usr/local/bin/airflow scheduler
airflow    160    65  0 Jun12 ?        00:00:00 /usr/bin/python
/usr/local/bin/airflow scheduler
airflow    161    65  0 Jun12 ?        00:00:00 /usr/bin/python
/usr/local/bin/airflow scheduler
airflow    163    64  0 Jun12 ?        00:00:08 gunicorn: master
[airflow.www.app:cached_app()]
airflow    168   163  0 Jun12 ?        00:00:18 gunicorn: worker
[airflow.www.app:cached_app()]
airflow    170   163  0 Jun12 ?        00:00:13 gunicorn: worker
[airflow.www.app:cached_app()]
airflow    171   163  0 Jun12 ?        00:00:08 gunicorn: worker
[airflow.www.app:cached_app()]
airflow    174   163  0 Jun12 ?        00:00:08 gunicorn: worker
[airflow.www.app:cached_app()]
airflow   7627     0  0 Jun12 ?        00:00:00 bash
airflow   8091  7627  0 Jun12 ?        00:00:00 python
airflow  28808     0  0 16:44 ?        00:00:00 bash
airflow  28823 28808  0 16:44 ?        00:00:00 ps -ef

On Mon, Jun 13, 2016 at 8:42 AM, Maxime Beauchemin <
maximebeauchemin@gmail.com> wrote:

> Can you confirm that it's the scheduler process using that CPU?
>
> The SCHEDULER_HEARTBEAT_SEC configuration defines a minimum duration for
> scheduling cycles, where the scheduler evaluates all active DagRun and
> attempts to kick off task instances whose dependencies are met. Once the
> cycle is done, the scheduler should sleep until the next heartbeat, so CPU
> should look spiky.
>
> Max
>
> On Mon, Jun 13, 2016 at 8:26 AM, harish singh <harish.singh22@gmail.com>
> wrote:
>
> > Yup, I tried changing the scheduler heartbeat to 60 seconds..
> > Apart from not getting any update for 60 seconds, What are the side
> effects
> > of changing the two heartbeats? Shouldn't impact performance?
> >
> > Also, I understand this cpu usage if there are 100s of dags. But with
> just
> > one active dag, doesnt 70% seem high? Esp in my case where there are only
> > 10 tasks in the dag making only curls (BashOperators).
> >
> > Also, a side now, in a different environment where we have 10 dags
> active,
> > the cpu usage stays in the same 70-80% range.
> >
> > On Mon, Jun 13, 2016, 8:14 AM Maxime Beauchemin <
> > maximebeauchemin@gmail.com>
> > wrote:
> >
> > > The scheduler constantly attempts to schedule tasks, interacting with
> the
> > > database and reloading DAG definition. In most larg-ish environments,
> > > burning up to a CPU to run the scheduler doesn't seem outrageous to me.
> > >
> > > If you want to reduce the CPU load related to the scheduler check out
> > > SCHEDULER_HEARTBEAT_SEC and MAX_THREADS in the scheduler section of
> > > `airflow.cfg`
> > >
> > > Max
> > >
> > > On Sun, Jun 12, 2016 at 1:24 PM, harish singh <
> harish.singh22@gmail.com>
> > > wrote:
> > >
> > > > Hi guys,
> > > >
> > > > We are running airflow (for about 3 months now) inside a docker
> > container
> > > > on aws.
> > > >
> > > > I just did a docker stats to check whats going on. The cpu
> consumption
> > is
> > > > huge.
> > > > We have around 15 DAGS. Only one DAG is turned ON. the remaining are
> > OFF.
> > > > The DAG runs with a HOURLY schedule.
> > > >
> > > > Right now, airflow is consuming almost 1 complete core.
> > > > It seems there is some unnecessary spinning?
> > > > This doesnt look like the right behavior.
> > > > Is there a bug already filed for this? Or am not sure if there is
> > > something
> > > > incorrect in the way I am using the airflow configuration.
> > > >
> > > > CONTAINER           CPU %               MEM USAGE / LIMIT     MEM %
> > > >       NET I/O               BLOCK I/O
> > > > CCC                         68.17%              619.7 MB / 2.147 GB
> > > > 28.85%              1.408 GB / 939.4 MB   7.856 MB / 0 B
> > > > XXX                          64.36%              619.4 MB / 2.147 GB
> > > > 28.84%              1.211 GB / 807.6 MB   7.856 MB / 0 B
> > > >
> > > >
> > > > Ariflow version 1.7.0
> > > >
> > > > Airflow config:
> > > >
> > > > sql_alchemy_pool_size = 5
> > > > sql_alchemy_pool_recycle = 3600
> > > > parallelism = 8
> > > > dag_concurrency = 8
> > > > max_active_runs_per_dag = 8
> > > >
> > > >
> > > >
> > > > Thanks,
> > > >
> > > > Harish
> > > >
> > >
> >
>

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