Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-27 Thread Tejun Heo
On Tue, Oct 27, 2015 at 06:56:42AM +0100, Mike Galbraith wrote: > > Well, if you think certain things are being missed, please speak up. > > Not in some media campaign way but with technical reasoning and > > justifications. > > Inserting a middle-man is extremely unlikely to improve performance.

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-27 Thread Mike Galbraith
On Tue, 2015-10-27 at 15:00 +0900, Tejun Heo wrote: > On Tue, Oct 27, 2015 at 06:56:42AM +0100, Mike Galbraith wrote: > > > Well, if you think certain things are being missed, please speak up. > > > Not in some media campaign way but with technical reasoning and > > > justifications. > > > >

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-26 Thread Tejun Heo
Hello, Mike. On Sun, Oct 25, 2015 at 04:43:33AM +0100, Mike Galbraith wrote: > I don't think it's weird, it's just a thought wrt where pigeon holing > could lead: If you filter out current users who do so in a manner you > consider to be in some way odd, when all the filtering is done, you may >

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-26 Thread Mike Galbraith
On Tue, 2015-10-27 at 12:16 +0900, Tejun Heo wrote: > Hello, Mike. > > On Sun, Oct 25, 2015 at 04:43:33AM +0100, Mike Galbraith wrote: > > I don't think it's weird, it's just a thought wrt where pigeon holing > > could lead: If you filter out current users who do so in a manner you > > consider

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-26 Thread Tejun Heo
Hello, On Tue, Oct 27, 2015 at 06:42:11AM +0100, Mike Galbraith wrote: > Sure, sounds fine, I just fervently hope that the below is foul swamp > gas having nothing what so ever to do with your definition of "saner". lol, idk, you keep taking things in weird directions. Let's just stay

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-26 Thread Mike Galbraith
On Tue, 2015-10-27 at 14:46 +0900, Tejun Heo wrote: > Hello, > > On Tue, Oct 27, 2015 at 06:42:11AM +0100, Mike Galbraith wrote: > > Sure, sounds fine, I just fervently hope that the below is foul swamp > > gas having nothing what so ever to do with your definition of "saner". > > lol, idk, you

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-26 Thread Peter Zijlstra
On Sun, Oct 25, 2015 at 02:17:23PM +0100, Florian Weimer wrote: > On 10/25/2015 12:58 PM, Theodore Ts'o wrote: > > > Well, I was thinking we could just teach them to use > > "syscall(SYS_gettid)". > > Right, and that's easier if TIDs are officially part of the GNU API. > > I think the worry is

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-25 Thread Florian Weimer
On 10/25/2015 12:58 PM, Theodore Ts'o wrote: > Well, I was thinking we could just teach them to use > "syscall(SYS_gettid)". Right, and that's easier if TIDs are officially part of the GNU API. I think the worry is that some future system might have TIDs which do not share the PID space, or are

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-25 Thread Theodore Ts'o
On Sun, Oct 25, 2015 at 10:33:32AM +0100, Ingo Molnar wrote: > > Hm, that's weird - all our sched_*() system call APIs that set task > scheduling > priorities are fundamentally per thread, not per process. Same goes for the > old > sys_nice() interface. The scheduler has no real notion of

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-25 Thread Ingo Molnar
* Linus Torvalds wrote: > On Sun, Oct 25, 2015 at 11:18 AM, Tejun Heo wrote: > > > > We definitely need to weigh the inputs from heavy users but also need to > > discern the actual problems which need to be solved from the specific > >

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-25 Thread Florian Weimer
On 10/25/2015 11:41 AM, Theodore Ts'o wrote: > On Sun, Oct 25, 2015 at 10:33:32AM +0100, Ingo Molnar wrote: >> >> Hm, that's weird - all our sched_*() system call APIs that set task >> scheduling >> priorities are fundamentally per thread, not per process. Same goes for the >> old >>

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-25 Thread Theodore Ts'o
On Sun, Oct 25, 2015 at 11:47:04AM +0100, Florian Weimer wrote: > On 10/25/2015 11:41 AM, Theodore Ts'o wrote: > > On Sun, Oct 25, 2015 at 10:33:32AM +0100, Ingo Molnar wrote: > >> > >> Hm, that's weird - all our sched_*() system call APIs that set task > >> scheduling > >> priorities are

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-24 Thread Tejun Heo
Hello, Mike. On Sat, Oct 24, 2015 at 06:36:07AM +0200, Mike Galbraith wrote: > On Sat, 2015-10-24 at 07:21 +0900, Tejun Heo wrote: > > > It'd be a step back in usability only for users who have been using > > cgroups in fringing ways which can't be justified for ratification and > > we do want

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-24 Thread Mike Galbraith
On Sun, 2015-10-25 at 11:18 +0900, Tejun Heo wrote: > Hello, Mike. > > On Sat, Oct 24, 2015 at 06:36:07AM +0200, Mike Galbraith wrote: > > On Sat, 2015-10-24 at 07:21 +0900, Tejun Heo wrote: > > > > > It'd be a step back in usability only for users who have been using > > > cgroups in fringing

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-24 Thread Linus Torvalds
On Sun, Oct 25, 2015 at 11:18 AM, Tejun Heo wrote: > > We definitely need to weigh the inputs from heavy users but also need > to discern the actual problems which need to be solved from the > specific mechanisms chosen to solve them. Let's please keep the > discussions

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-23 Thread Mike Galbraith
On Sat, 2015-10-24 at 07:21 +0900, Tejun Heo wrote: > It'd be a step back in usability only for users who have been using > cgroups in fringing ways which can't be justified for ratification and > we do want to actively filter those out. Of all the cgroup signal currently in existence, seems the

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-23 Thread Tejun Heo
Hello, Paul. On Thu, Oct 15, 2015 at 04:42:37AM -0700, Paul Turner wrote: > > The thing which bothers me the most is that cpuset behavior is > > different from global case for no good reason. > > I've tried to explain above that I believe there are reasonable > reasons for it working the way it

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-15 Thread Paul Turner
On Thu, Oct 1, 2015 at 11:46 AM, Tejun Heo wrote: > Hello, Paul. > > Sorry about the delay. Things were kinda hectic in the past couple > weeks. Likewise :-( > > On Fri, Sep 18, 2015 at 04:27:07AM -0700, Paul Turner wrote: >> On Sat, Sep 12, 2015 at 7:40 AM, Tejun Heo

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-10-01 Thread Tejun Heo
Hello, Paul. Sorry about the delay. Things were kinda hectic in the past couple weeks. On Fri, Sep 18, 2015 at 04:27:07AM -0700, Paul Turner wrote: > On Sat, Sep 12, 2015 at 7:40 AM, Tejun Heo wrote: > > On Wed, Sep 09, 2015 at 05:49:31AM -0700, Paul Turner wrote: > >> I do

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-18 Thread Paul Turner
On Sat, Sep 12, 2015 at 7:40 AM, Tejun Heo wrote: > Hello, > > On Wed, Sep 09, 2015 at 05:49:31AM -0700, Paul Turner wrote: >> I do not think this is a layering problem. This is more like C++: >> there is no sane way to concurrently use all the features available, >> however,

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-17 Thread Peter Zijlstra
On Thu, Sep 17, 2015 at 10:53:09AM -0400, Tejun Heo wrote: > > I'd be happy to fail a CPU down for user tasks where this is the last > > runnable CPU of. > > So, yeah, we need to keep these things consistent across global and > cgroup cases. > Ok, I'll go extend the sysctl_sched_strict_affinity

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-17 Thread Peter Zijlstra
On Thu, Sep 17, 2015 at 11:52:45AM -0400, Tejun Heo wrote: > Hello, > > On Thu, Sep 17, 2015 at 05:10:49PM +0200, Peter Zijlstra wrote: > > Subject: sched: Refuse to unplug a CPU if this will violate user task > > affinity > > > > Its bad policy to allow unplugging a CPU for which a user set

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-17 Thread Tejun Heo
Hello, On Thu, Sep 17, 2015 at 05:10:49PM +0200, Peter Zijlstra wrote: > Subject: sched: Refuse to unplug a CPU if this will violate user task affinity > > Its bad policy to allow unplugging a CPU for which a user set explicit > affinity, either strictly on this CPU or in case this was the last

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-17 Thread Tejun Heo
Hello, On Thu, Sep 17, 2015 at 04:35:27PM +0200, Peter Zijlstra wrote: > On Sat, Sep 12, 2015 at 10:40:07AM -0400, Tejun Heo wrote: > > So, one of the problems is that the kernel can't have tasks w/o > > runnable CPUs, so we have to some workaround when, for whatever > > reason, a task ends up

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-17 Thread Peter Zijlstra
On Thu, Sep 17, 2015 at 04:35:27PM +0200, Peter Zijlstra wrote: > I'd be happy to fail a CPU down for user tasks where this is the last > runnable CPU of. A little like so. Completely untested. --- Subject: sched: Refuse to unplug a CPU if this will violate user task affinity Its bad policy to

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-17 Thread Peter Zijlstra
On Sat, Sep 12, 2015 at 10:40:07AM -0400, Tejun Heo wrote: > So, one of the problems is that the kernel can't have tasks w/o > runnable CPUs, so we have to some workaround when, for whatever > reason, a task ends up with no CPU that it can run on. No, just refuse that configuration. > You say

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-17 Thread Tejun Heo
Paul? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-12 Thread Tejun Heo
Hello, On Wed, Sep 09, 2015 at 05:49:31AM -0700, Paul Turner wrote: > I do not think this is a layering problem. This is more like C++: > there is no sane way to concurrently use all the features available, > however, reasonably self-consistent subsets may be chosen. That's just admitting

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-09 Thread Paul Turner
[ Picking this back up, I was out of the country last week. Note that we are also wrestling with some DMARC issues as it was just activated for Google.com so apologies if people do not receive this directly. ] On Tue, Aug 25, 2015 at 2:02 PM, Tejun Heo wrote: > Hello, > > On

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-09-02 Thread Tejun Heo
Paul? Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-25 Thread Tejun Heo
Hello, Paul. On Mon, Aug 24, 2015 at 04:15:59PM -0700, Paul Turner wrote: Hmmm... if that's the case, would limiting iops on those IO devices (or classes of them) work? qemu already implements IO limit mechanism after all. No. 1) They should proceed at the maximum rate that they can

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-25 Thread Peter Zijlstra
On Tue, Aug 25, 2015 at 11:24:42AM +0200, Ingo Molnar wrote: * Paul Turner p...@google.com wrote: Anyways, a point here is that threads of the same process competing isn't a new problem. There are many ways to make those threads play nice as the application itself often has to be

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-25 Thread Ingo Molnar
* Paul Turner p...@google.com wrote: Anyways, a point here is that threads of the same process competing isn't a new problem. There are many ways to make those threads play nice as the application itself often has to be involved anyway, especially for something like qemu which is

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-25 Thread Tejun Heo
Hello, On Mon, Aug 24, 2015 at 04:06:39PM -0700, Paul Turner wrote: This is an erratic behavior on cpuset's part tho. Nothing else behaves this way and it's borderline buggy. It's actually the only sane possible interaction here. If you don't overwrite the masks you can no longer

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-25 Thread Tejun Heo
Hello, Kame. On Tue, Aug 25, 2015 at 11:36:25AM +0900, Kamezawa Hiroyuki wrote: I think I should explain my customer's use case of qemu + cpuset/cpu (via libvirt) (1) Isolating hypervisor thread. As already discussed, hypervisor threads are isolated by cpuset. But their purpose is

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Austin S Hemmelgarn
On 2015-08-22 14:29, Tejun Heo wrote: Hello, Paul. On Fri, Aug 21, 2015 at 12:26:30PM -0700, Paul Turner wrote: ... A very concrete example of the above is a virtual machine in which you want to guarantee scheduling for the vCPU threads which must schedule beside many hypervisor support

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Tejun Heo
Hello, Austin. On Mon, Aug 24, 2015 at 11:47:02AM -0400, Austin S Hemmelgarn wrote: Just to learn more, what sort of hypervisor support threads are we talking about? They would have to consume considerable amount of cpu cycles for problems like this to be relevant and be dynamic in numbers

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Mike Galbraith
On Mon, 2015-08-24 at 13:04 -0400, Tejun Heo wrote: Hello, Austin. On Mon, Aug 24, 2015 at 11:47:02AM -0400, Austin S Hemmelgarn wrote: Just to learn more, what sort of hypervisor support threads are we talking about? They would have to consume considerable amount of cpu cycles for

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Tejun Heo
Hello, On Mon, Aug 24, 2015 at 01:54:08PM -0700, Paul Turner wrote: That alone doesn't require hierarchical resource distribution tho. Setting nice levels reasonably is likely to alleviate most of the problem. Nice is not sufficient here. There could be arbitrarily many threads within

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Tejun Heo
Hello, Austin. On Mon, Aug 24, 2015 at 04:00:49PM -0400, Austin S Hemmelgarn wrote: That alone doesn't require hierarchical resource distribution tho. Setting nice levels reasonably is likely to alleviate most of the problem. In the cases I've dealt with this myself, nice levels didn't cut

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Mon, Aug 24, 2015 at 10:04 AM, Tejun Heo t...@kernel.org wrote: Hello, Austin. On Mon, Aug 24, 2015 at 11:47:02AM -0400, Austin S Hemmelgarn wrote: Just to learn more, what sort of hypervisor support threads are we talking about? They would have to consume considerable amount of cpu

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Austin S Hemmelgarn
On 2015-08-24 13:04, Tejun Heo wrote: Hello, Austin. On Mon, Aug 24, 2015 at 11:47:02AM -0400, Austin S Hemmelgarn wrote: Just to learn more, what sort of hypervisor support threads are we talking about? They would have to consume considerable amount of cpu cycles for problems like this to be

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Mon, Aug 24, 2015 at 1:25 PM, Tejun Heo t...@kernel.org wrote: Hello, Austin. On Mon, Aug 24, 2015 at 04:00:49PM -0400, Austin S Hemmelgarn wrote: That alone doesn't require hierarchical resource distribution tho. Setting nice levels reasonably is likely to alleviate most of the problem.

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Mon, Aug 24, 2015 at 2:02 PM, Tejun Heo t...@kernel.org wrote: Hello, On Mon, Aug 24, 2015 at 01:54:08PM -0700, Paul Turner wrote: That alone doesn't require hierarchical resource distribution tho. Setting nice levels reasonably is likely to alleviate most of the problem. Nice is not

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Tejun Heo
Hello, On Mon, Aug 24, 2015 at 02:10:17PM -0700, Paul Turner wrote: Suppose that we have 10 vcpu threads and 100 support threads. Suppose that we want the support threads to receive up to 10% of the time available to the VM as a whole on that machine. If I have one particular support thread

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Mon, Aug 24, 2015 at 2:36 PM, Tejun Heo t...@kernel.org wrote: Hello, Paul. On Mon, Aug 24, 2015 at 01:52:01PM -0700, Paul Turner wrote: We typically share our machines between many jobs, these jobs can have cores that are private (and not shared with other jobs) and cores that are shared

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Sat, Aug 22, 2015 at 11:29 AM, Tejun Heo t...@kernel.org wrote: Hello, Paul. On Fri, Aug 21, 2015 at 12:26:30PM -0700, Paul Turner wrote: ... A very concrete example of the above is a virtual machine in which you want to guarantee scheduling for the vCPU threads which must schedule

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Mon, Aug 24, 2015 at 2:17 PM, Tejun Heo t...@kernel.org wrote: Hello, On Mon, Aug 24, 2015 at 02:10:17PM -0700, Paul Turner wrote: Suppose that we have 10 vcpu threads and 100 support threads. Suppose that we want the support threads to receive up to 10% of the time available to the VM as

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Tejun Heo
Hello, Paul. On Mon, Aug 24, 2015 at 02:00:54PM -0700, Paul Turner wrote: Hmmm... I'm trying to understand the usecases where having hierarchy inside a process are actually required so that we don't end up doing something complex unnecessarily. So far, it looks like an easy alternative

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Tejun Heo
Hello, Paul. On Mon, Aug 24, 2015 at 01:52:01PM -0700, Paul Turner wrote: We typically share our machines between many jobs, these jobs can have cores that are private (and not shared with other jobs) and cores that are shared (general purpose cores accessible to all jobs on the same

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Tejun Heo
On Mon, Aug 24, 2015 at 02:19:29PM -0700, Paul Turner wrote: Would it be possible for you to give realistic and concrete examples? I'm not trying to play down the use cases but concrete examples are usually helpful at putting things in perspective. I don't think there's anything that's

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Mon, Aug 24, 2015 at 2:12 PM, Tejun Heo t...@kernel.org wrote: Hello, Paul. On Mon, Aug 24, 2015 at 02:00:54PM -0700, Paul Turner wrote: Hmmm... I'm trying to understand the usecases where having hierarchy inside a process are actually required so that we don't end up doing something

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Mon, Aug 24, 2015 at 2:40 PM, Tejun Heo t...@kernel.org wrote: On Mon, Aug 24, 2015 at 02:19:29PM -0700, Paul Turner wrote: Would it be possible for you to give realistic and concrete examples? I'm not trying to play down the use cases but concrete examples are usually helpful at putting

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Mon, Aug 24, 2015 at 3:49 PM, Tejun Heo t...@kernel.org wrote: Hello, On Mon, Aug 24, 2015 at 03:03:05PM -0700, Paul Turner wrote: Hmm... I was hoping for an actual configurations and usage scenarios. Preferably something people can set up and play with. This is much easier to set up

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Paul Turner
On Mon, Aug 24, 2015 at 3:19 PM, Tejun Heo t...@kernel.org wrote: Hey, On Mon, Aug 24, 2015 at 02:58:23PM -0700, Paul Turner wrote: Why isn't it? Because the programs themselves might try to override it? The major reasons are: 1) Isolation. Doing everything with sched_setaffinity

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Tejun Heo
Hello, On Mon, Aug 24, 2015 at 03:03:05PM -0700, Paul Turner wrote: Hmm... I was hoping for an actual configurations and usage scenarios. Preferably something people can set up and play with. This is much easier to set up and play with synthetically. Just create the 10 threads and 100

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Tejun Heo
Hey, On Mon, Aug 24, 2015 at 02:58:23PM -0700, Paul Turner wrote: Why isn't it? Because the programs themselves might try to override it? The major reasons are: 1) Isolation. Doing everything with sched_setaffinity means that programs can use arbitrary resources if they desire.

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-24 Thread Kamezawa Hiroyuki
On 2015/08/25 8:15, Paul Turner wrote: On Mon, Aug 24, 2015 at 3:49 PM, Tejun Heo t...@kernel.org wrote: Hello, On Mon, Aug 24, 2015 at 03:03:05PM -0700, Paul Turner wrote: Hmm... I was hoping for an actual configurations and usage scenarios. Preferably something people can set up and play

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-22 Thread Tejun Heo
Hello, Paul. On Fri, Aug 21, 2015 at 12:26:30PM -0700, Paul Turner wrote: ... A very concrete example of the above is a virtual machine in which you want to guarantee scheduling for the vCPU threads which must schedule beside many hypervisor support threads. A hierarchy is the only way to

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-21 Thread Paul Turner
On Tue, Aug 18, 2015 at 1:31 PM, Tejun Heo t...@kernel.org wrote: Hello, Paul. On Mon, Aug 17, 2015 at 09:03:30PM -0700, Paul Turner wrote: 2) Control within an address-space. For subsystems with fungible resources, e.g. CPU, it can be useful for an address space to partition its own

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-20 Thread Tejun Heo
Hey, Mike. On Thu, Aug 20, 2015 at 06:00:59AM +0200, Mike Galbraith wrote: If create/attach/detach/destroy aren't hot paths, what is? Those are fork/exec/exit cgroup analogs. If you have thousands upon thousands of Things like page faults? cgroup controllers hook into subsystems and their

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-20 Thread Mike Galbraith
On Thu, 2015-08-20 at 00:52 -0700, Tejun Heo wrote: Hmmm... I think this discussion got pretty badly derailed at this point. If I'm not mistaken, you're talking about tens or a few hundred millisecs of latency per migration which no longer exists and won't ever come back and the discussion

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-19 Thread Tejun Heo
Hello, Kame. On Wed, Aug 19, 2015 at 08:39:43AM +0900, Kamezawa Hiroyuki wrote: An actual per-thread use case in our customers is qemu-kvm + cpuset. customers pin each vcpus and qemu-kvm's worker threads to cpus. For example, pinning 4 vcpus to cpu 2-6 and pinning qemu main thread and

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-19 Thread Tejun Heo
Hello, Mike. On Wed, Aug 19, 2015 at 05:23:40AM +0200, Mike Galbraith wrote: Hm. I know of a big data outfit to which attach/detach performance was important enough for them to have plucked an old experimental overhead reduction hack (mine) off lkml, and shipped it. It must have mattered a

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-19 Thread Mike Galbraith
On Wed, 2015-08-19 at 09:41 -0700, Tejun Heo wrote: Most problems can be solved in different ways and I'm doubtful that e.g. bouncing jobs to worker threads would be more expensive than migrating the worker back and forth in a lot of cases. If migrating threads around floats somebody's boat,

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-18 Thread Tejun Heo
Hello, Paul. On Mon, Aug 17, 2015 at 09:03:30PM -0700, Paul Turner wrote: 2) Control within an address-space. For subsystems with fungible resources, e.g. CPU, it can be useful for an address space to partition its own threads. Losing the capability to do this against the CPU controller

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-18 Thread Mike Galbraith
On Tue, 2015-08-18 at 13:31 -0700, Tejun Heo wrote: So, this is a trade-off we're consciously making. If there are common-enough use cases which require jumping across different cgroup domains, we'll try to figure out a way to accomodate those but by default migration is a very cold and

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-18 Thread Kamezawa Hiroyuki
On 2015/08/19 5:31, Tejun Heo wrote: Hello, Paul. On Mon, Aug 17, 2015 at 09:03:30PM -0700, Paul Turner wrote: 2) Control within an address-space. For subsystems with fungible resources, e.g. CPU, it can be useful for an address space to partition its own threads. Losing the capability to do

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-17 Thread Paul Turner
Apologies for the repeat. Gmail ate its plain text setting for some reason. Shame bells. On Mon, Aug 17, 2015 at 9:02 PM, Paul Turner p...@google.com wrote: On Wed, Aug 5, 2015 at 7:31 AM, Tejun Heo t...@kernel.org wrote: Hello, On Wed, Aug 05, 2015 at 11:10:36AM +0200, Peter Zijlstra

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-17 Thread Tejun Heo
Hello, Peter. Do we have an agreement on the sched changes? Thanks a lot. -- tejun -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-05 Thread Peter Zijlstra
On Tue, Aug 04, 2015 at 11:10:17AM -0400, Tejun Heo wrote: Hello, Peter. On Tue, Aug 04, 2015 at 11:07:11AM +0200, Peter Zijlstra wrote: What about the unified hierarchy stuff cannot deal with per-task controllers? _That_ was the biggest problem from what I can remember, and I see no

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-05 Thread Tejun Heo
Hello, On Wed, Aug 05, 2015 at 11:10:36AM +0200, Peter Zijlstra wrote: I've been thinking about it and I'm now convinced that cgroups just is the wrong interface to require each application to be programming against. But people are doing it. So you must give them something. You cannot

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-04 Thread Peter Zijlstra
On Mon, Aug 03, 2015 at 06:41:29PM -0400, Tejun Heo wrote: While the cpu controller doesn't have any functional problems, there are a couple interface issues which can be addressed in the v2 interface. * cpuacct being a separate controller. This separation is artificial and rather

Re: [PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-04 Thread Tejun Heo
Hello, Peter. On Tue, Aug 04, 2015 at 11:07:11AM +0200, Peter Zijlstra wrote: What about the unified hierarchy stuff cannot deal with per-task controllers? _That_ was the biggest problem from what I can remember, and I see no proposed resolution for that here. I've been thinking about it

[PATCH 3/3] sched: Implement interface for cgroup unified hierarchy

2015-08-03 Thread Tejun Heo
While the cpu controller doesn't have any functional problems, there are a couple interface issues which can be addressed in the v2 interface. * cpuacct being a separate controller. This separation is artificial and rather pointless as demonstrated by most use cases co-mounting the two