From: Rami Rosen <ramirose@gmail.com>
To: Shirley Avishour <shirley@imvisiontech.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] running dpdk application on the same machine with other none dpdk application
Date: Wed, 30 Jan 2019 09:26:01 +0200 [thread overview]
Message-ID: <CAHLOa7QbiPdQynjenNMqtT06v1FEsCuucDhwQyw1ETbyOM1uyw@mail.gmail.com> (raw)
In-Reply-To: <CACn717hy2uAJ1mV-UHLtm1cTvsvYdHe_v_Xs=sUu+TVhsZF=5Q@mail.gmail.com>
Hi Shirley,
I think you are right, isolcpus is for userspace threads.
...
"Use the isolcpus parameter on the kernel command line to isolate certain
cores from user-space tasks."
...
See:
https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/7/html/performance_tuning_guide/sect-red_hat_enterprise_linux-performance_tuning_guide-cpu-configuration_suggestions
So if there is no way to configure JVM to use specified kernel cores (and I
am afraid there is no such way),
I am not sure how this can be solved.
Regards,
Rami Rosen
On Wed, Jan 30, 2019 at 9:05 AM Shirley Avishour <shirley@imvisiontech.com>
wrote:
> Hi Rami,
>
> This is the printout for cat /proc/cmdline
> BOOT_IMAGE=/boot/vmlinuz-4.15.0-43-generic
> root=UUID=6f1a210b-a30f-456d-bf16-bbb210da5666 ro default_hugepagesz=2M
> hugepagesz=2M hugepages=4096 isolcpus=1-5 nohz_full=1-5 rcu_nocbs=1-5
>
> The requires cpus are in fact isolated but jvm generate some kernel
> threads as well and I'm afraid that these kernel space threads eventually
> use all cores. isolcpus is not applies on kernel space threads.
>
> Shirley.
>
>
>
> On Wed, Jan 30, 2019 at 8:57 AM Rami Rosen <ramirose@gmail.com> wrote:
>
>> Hi Shirley,
>> >Running java based applications on the same server with a dpdk based
>> application has an impact on the dpdk performance.
>> Probably since the JVM generates kernel based processes. I
>>
>> This is true, but as far as I know, using isolcpus should prevent these
>> processes to run on the isolated cores.
>>
>> Just to be on the safe side: did you make sure with cat /proc/cmdline on
>> the kernel you are actually running indeed
>> has the "isolcpus=1-5" you added in grub ? sometimes, especially in
>> multi OS hosts, adding entries in /etc/default/grub and running grub2-mkconfig
>> is not enough, if you boot from a different partition.
>>
>> Regards,
>> Rami Rosen
>>
>>
>>
--
regards,
Rami Rosen
next prev parent reply other threads:[~2019-01-30 7:26 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-29 16:32 Shirley Avishour
2019-01-30 6:09 ` Rami Rosen
2019-01-30 6:31 ` Shirley Avishour
2019-01-30 6:57 ` Rami Rosen
2019-01-30 7:05 ` Shirley Avishour
2019-01-30 7:26 ` Rami Rosen [this message]
2019-01-30 7:47 ` Shirley Avishour
2019-01-30 8:18 ` Rami Rosen
2019-01-30 8:27 ` Shirley Avishour
2019-01-30 8:30 ` Shirley Avishour
2019-01-30 8:40 ` Rami Rosen
2019-01-30 8:45 ` Shirley Avishour
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