Re: [PATCH v2 0/4] timer: Improve itimers scalability

Removing dependency to the database code is trivial. It's just 100 lines that launch lots of threads and do NUMA-aware memory accesses so that remote NUMA access cost does not affect the benchmark. It's just a bit tedious to convert the C++11 code into C/pthread. C++11 really spoiled me.

Re: [PATCH v2 0/4] timer: Improve itimers scalability

On Fri, 2015-10-16 at 09:12 +0200, Ingo Molnar wrote: > * Jason Low wrote: > > > > > With this patch set (along with commit 1018016c706f mentioned above), > > > > the performance hit of itimers almost completely goes away on the > > > > 16 socket system. > > > > > > > > Jason Low (4): > > > >

Re: [PATCH v2 0/4] timer: Improve itimers scalability

* Jason Low wrote: > > > With this patch set (along with commit 1018016c706f mentioned above), > > > the performance hit of itimers almost completely goes away on the > > > 16 socket system. > > > > > > Jason Low (4): > > > timer: Optimize fastpath_timer_check() > > > timer: Check thread

Re: [PATCH v2 0/4] timer: Improve itimers scalability

Removing dependency to the database code is trivial. It's just 100 lines that launch lots of threads and do NUMA-aware memory accesses so that remote NUMA access cost does not affect the benchmark. It's just a bit tedious to convert the C++11 code into C/pthread. C++11 really spoiled me.

Re: [PATCH v2 0/4] timer: Improve itimers scalability

On Fri, 2015-10-16 at 09:12 +0200, Ingo Molnar wrote: > * Jason Low wrote: > > > > > With this patch set (along with commit 1018016c706f mentioned above), > > > > the performance hit of itimers almost completely goes away on the > > > > 16 socket system. > > > > > > > > Jason

Re: [PATCH v2 0/4] timer: Improve itimers scalability

* Jason Low wrote: > > > With this patch set (along with commit 1018016c706f mentioned above), > > > the performance hit of itimers almost completely goes away on the > > > 16 socket system. > > > > > > Jason Low (4): > > > timer: Optimize fastpath_timer_check() > > >

Re: [PATCH v2 0/4] timer: Improve itimers scalability

On Thu, 2015-10-15 at 10:47 +0200, Ingo Molnar wrote: > * Jason Low wrote: > > > While running a database workload on a 16 socket machine, there were > > scalability issues related to itimers. The following link contains a > > more detailed summary of the issues at the application level. > > >

Re: [PATCH v2 0/4] timer: Improve itimers scalability

On Wed, 2015-10-14 at 17:18 -0400, George Spelvin wrote: > I'm going to give 4/4 a closer look to see if the races with timer > expiration make more sense to me than last time around. > (E.g. do CPU time signals even work in CONFIG_NO_HZ_FULL?) > > But although I haven't yet convinced myself the

Re: [PATCH v2 0/4] timer: Improve itimers scalability

On Wed, Oct 14, 2015 at 05:18:27PM -0400, George Spelvin wrote: > I'm going to give 4/4 a closer look to see if the races with timer > expiration make more sense to me than last time around. > (E.g. do CPU time signals even work in CONFIG_NO_HZ_FULL?) Those enqueued with timer_settime() do work.

Re: [PATCH v2 0/4] timer: Improve itimers scalability

* Jason Low wrote: > While running a database workload on a 16 socket machine, there were > scalability issues related to itimers. The following link contains a > more detailed summary of the issues at the application level. > > https://lkml.org/lkml/2015/8/26/737 > > Commit 1018016c706f

Re: [PATCH v2 0/4] timer: Improve itimers scalability

On Wed, Oct 14, 2015 at 05:18:27PM -0400, George Spelvin wrote: > I'm going to give 4/4 a closer look to see if the races with timer > expiration make more sense to me than last time around. > (E.g. do CPU time signals even work in CONFIG_NO_HZ_FULL?) Those enqueued with timer_settime() do work.

Re: [PATCH v2 0/4] timer: Improve itimers scalability

* Jason Low wrote: > While running a database workload on a 16 socket machine, there were > scalability issues related to itimers. The following link contains a > more detailed summary of the issues at the application level. > > https://lkml.org/lkml/2015/8/26/737 > >

Re: [PATCH v2 0/4] timer: Improve itimers scalability

On Wed, 2015-10-14 at 17:18 -0400, George Spelvin wrote: > I'm going to give 4/4 a closer look to see if the races with timer > expiration make more sense to me than last time around. > (E.g. do CPU time signals even work in CONFIG_NO_HZ_FULL?) > > But although I haven't yet convinced myself the

Re: [PATCH v2 0/4] timer: Improve itimers scalability

On Thu, 2015-10-15 at 10:47 +0200, Ingo Molnar wrote: > * Jason Low wrote: > > > While running a database workload on a 16 socket machine, there were > > scalability issues related to itimers. The following link contains a > > more detailed summary of the issues at the

Re: [PATCH v2 0/4] timer: Improve itimers scalability

I'm going to give 4/4 a closer look to see if the races with timer expiration make more sense to me than last time around. (E.g. do CPU time signals even work in CONFIG_NO_HZ_FULL?) But although I haven't yet convinced myself the current code is right, the changes don't seem to make it any worse.

[PATCH v2 0/4] timer: Improve itimers scalability

While running a database workload on a 16 socket machine, there were scalability issues related to itimers. The following link contains a more detailed summary of the issues at the application level. https://lkml.org/lkml/2015/8/26/737 Commit 1018016c706f addressed the issue with the

[PATCH v2 0/4] timer: Improve itimers scalability

While running a database workload on a 16 socket machine, there were scalability issues related to itimers. The following link contains a more detailed summary of the issues at the application level. https://lkml.org/lkml/2015/8/26/737 Commit 1018016c706f addressed the issue with the

Re: [PATCH v2 0/4] timer: Improve itimers scalability

I'm going to give 4/4 a closer look to see if the races with timer expiration make more sense to me than last time around. (E.g. do CPU time signals even work in CONFIG_NO_HZ_FULL?) But although I haven't yet convinced myself the current code is right, the changes don't seem to make it any worse.