Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 16 Jan 2018 16:57:45 +0100 Frederic Weisbecker wrote: > On Fri, Jan 12, 2018 at 02:22:58PM -0500, Luiz Capitulino wrote: > > On Thu, 4 Jan 2018 05:25:36 +0100 > > Frederic Weisbecker wrote: > > > > > When a CPU runs in full dynticks mode, a

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 16 Jan 2018 16:57:45 +0100 Frederic Weisbecker wrote: > On Fri, Jan 12, 2018 at 02:22:58PM -0500, Luiz Capitulino wrote: > > On Thu, 4 Jan 2018 05:25:36 +0100 > > Frederic Weisbecker wrote: > > > > > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > > > keep

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Fri, Jan 12, 2018 at 02:22:58PM -0500, Luiz Capitulino wrote: > On Thu, 4 Jan 2018 05:25:36 +0100 > Frederic Weisbecker wrote: > > > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > > keep the scheduler stats alive. However this residual tick is a

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Fri, Jan 12, 2018 at 02:22:58PM -0500, Luiz Capitulino wrote: > On Thu, 4 Jan 2018 05:25:36 +0100 > Frederic Weisbecker wrote: > > > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > > keep the scheduler stats alive. However this residual tick is a burden > > for bare

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Thu, 4 Jan 2018 05:25:36 +0100 Frederic Weisbecker wrote: > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > keep the scheduler stats alive. However this residual tick is a burden > for bare metal tasks that can't stand any interruption at all, or

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Thu, 4 Jan 2018 05:25:36 +0100 Frederic Weisbecker wrote: > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > keep the scheduler stats alive. However this residual tick is a burden > for bare metal tasks that can't stand any interruption at all, or want > to minimize

[PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for bare metal tasks that can't stand any interruption at all, or want to minimize them. Adding the boot parameter "isolcpus=nohz_offload" will now

[PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for bare metal tasks that can't stand any interruption at all, or want to minimize them. Adding the boot parameter "isolcpus=nohz_offload" will now

[PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for bare metal tasks that can't stand no interruption at all, or want to minimize them. Adding the boot parameter "isolcpus=nohz_offload" will now outsource

[PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for bare metal tasks that can't stand no interruption at all, or want to minimize them. Adding the boot parameter "isolcpus=nohz_offload" will now outsource

[PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for bare metal tasks that can't stand no interruption at all, or want to minimize them. Adding the boot parameter "isolcpus=nohz_offload" will now outsource

[PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for bare metal tasks that can't stand no interruption at all, or want to minimize them. Adding the boot parameter "isolcpus=nohz_offload" will now outsource

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Peter Zijlstra wrote: > On Tue, Dec 19, 2017 at 10:38:39AM -0600, Christopher Lameter wrote: > > And the term RT has been heavily abused by marketing folks to mean any > > number of things so people can use RT to refer to variety of things. So > > please always clarify what

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Peter Zijlstra wrote: > On Tue, Dec 19, 2017 at 10:38:39AM -0600, Christopher Lameter wrote: > > And the term RT has been heavily abused by marketing folks to mean any > > number of things so people can use RT to refer to variety of things. So > > please always clarify what

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Frederic Weisbecker wrote: > > The vmstat processing required per cpu area access. How does that work if > > the code is running on a remote processor? > > It seems that current::sched_class::task_tick() is ok with this, as it > uses per runqueues or per task datas. And both

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Frederic Weisbecker wrote: > > The vmstat processing required per cpu area access. How does that work if > > the code is running on a remote processor? > > It seems that current::sched_class::task_tick() is ok with this, as it > uses per runqueues or per task datas. And both

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, Dec 19, 2017 at 10:38:39AM -0600, Christopher Lameter wrote: > And the term RT has been heavily abused by marketing folks to mean any > number of things so people can use RT to refer to variety of things. So > please always clarify what you mean exactly. Do not _ever_ listen to

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, Dec 19, 2017 at 10:38:39AM -0600, Christopher Lameter wrote: > And the term RT has been heavily abused by marketing folks to mean any > number of things so people can use RT to refer to variety of things. So > please always clarify what you mean exactly. Do not _ever_ listen to

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Peter Zijlstra wrote: > > Depends what one means by RT. > > Real Time computing as per the literature. Any other definition is > wrong and confusing. That is an understanding of language rooted in the positivism of the early 20th century which was intending to assign a

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Peter Zijlstra wrote: > > Depends what one means by RT. > > Real Time computing as per the literature. Any other definition is > wrong and confusing. That is an understanding of language rooted in the positivism of the early 20th century which was intending to assign a

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

2017-12-19 17:03 UTC+01:00, Christopher Lameter : > On Tue, 19 Dec 2017, Frederic Weisbecker wrote: > >> Adding the boot parameter "isolcpus=nohz_offload" will now outsource >> these scheduler ticks to the global workqueue so that a housekeeping CPU >> handles that tick remotely. >

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

2017-12-19 17:03 UTC+01:00, Christopher Lameter : > On Tue, 19 Dec 2017, Frederic Weisbecker wrote: > >> Adding the boot parameter "isolcpus=nohz_offload" will now outsource >> these scheduler ticks to the global workqueue so that a housekeeping CPU >> handles that tick remotely. > > The vmstat

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

2017-12-19 10:19 UTC+01:00, Peter Zijlstra : > On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: >> When a CPU runs in full dynticks mode, a 1Hz tick remains in order to >> keep the scheduler stats alive. However this residual tick is a burden >> for

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

2017-12-19 10:19 UTC+01:00, Peter Zijlstra : > On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: >> When a CPU runs in full dynticks mode, a 1Hz tick remains in order to >> keep the scheduler stats alive. However this residual tick is a burden >> for Real-Time tasks that can't

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, Dec 19, 2017 at 10:01:46AM -0600, Christopher Lameter wrote: > On Tue, 19 Dec 2017, Peter Zijlstra wrote: > > > On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: > > > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > > > keep the scheduler stats

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, Dec 19, 2017 at 10:01:46AM -0600, Christopher Lameter wrote: > On Tue, 19 Dec 2017, Peter Zijlstra wrote: > > > On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: > > > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > > > keep the scheduler stats

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Frederic Weisbecker wrote: > Adding the boot parameter "isolcpus=nohz_offload" will now outsource > these scheduler ticks to the global workqueue so that a housekeeping CPU > handles that tick remotely. The vmstat processing required per cpu area access. How does that work

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Frederic Weisbecker wrote: > Adding the boot parameter "isolcpus=nohz_offload" will now outsource > these scheduler ticks to the global workqueue so that a housekeeping CPU > handles that tick remotely. The vmstat processing required per cpu area access. How does that work

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Peter Zijlstra wrote: > On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: > > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > > keep the scheduler stats alive. However this residual tick is a burden > > for Real-Time tasks that can't

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017, Peter Zijlstra wrote: > On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: > > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > > keep the scheduler stats alive. However this residual tick is a burden > > for Real-Time tasks that can't

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017 10:19:11 +0100 Peter Zijlstra wrote: > On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: > > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > > keep the scheduler stats alive. However this residual tick is a

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, 19 Dec 2017 10:19:11 +0100 Peter Zijlstra wrote: > On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: > > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > > keep the scheduler stats alive. However this residual tick is a burden > > for Real-Time

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > keep the scheduler stats alive. However this residual tick is a burden > for Real-Time tasks that can't stand no interruption at all. I'm not sure that is

Re: [PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

On Tue, Dec 19, 2017 at 04:23:57AM +0100, Frederic Weisbecker wrote: > When a CPU runs in full dynticks mode, a 1Hz tick remains in order to > keep the scheduler stats alive. However this residual tick is a burden > for Real-Time tasks that can't stand no interruption at all. I'm not sure that is

[PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for Real-Time tasks that can't stand no interruption at all. Adding the boot parameter "isolcpus=nohz_offload" will now outsource these scheduler ticks to

[PATCH 4/5] sched/isolation: Residual 1Hz scheduler tick offload

When a CPU runs in full dynticks mode, a 1Hz tick remains in order to keep the scheduler stats alive. However this residual tick is a burden for Real-Time tasks that can't stand no interruption at all. Adding the boot parameter "isolcpus=nohz_offload" will now outsource these scheduler ticks to