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Groups > linux.kernel > #1631586
| From | "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: TREE_SRCU slows hotplug by factor ~16 |
| Date | 2017-04-26 18:10 +0200 |
| Message-ID | <tAxFU-4AU-41@gated-at.bofh.it> (permalink) |
| References | (5 earlier) <tAhhL-2cM-11@gated-at.bofh.it> <tAwgO-3vw-15@gated-at.bofh.it> <tAx3d-46S-37@gated-at.bofh.it> <tAxmy-4e9-27@gated-at.bofh.it> <tAxwf-4hS-49@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, Apr 26, 2017 at 05:49:59PM +0200, Mike Galbraith wrote: > On Wed, 2017-04-26 at 08:44 -0700, Paul E. McKenney wrote: > > On Wed, Apr 26, 2017 at 05:26:20PM +0200, Mike Galbraith wrote: > > > On Wed, 2017-04-26 at 07:31 -0700, Paul E. McKenney wrote: > > > > > > > And a sneak preview, semi-tested. If you get a chance to run this, please > > > > let me know now it goes. > > > > > > That took 'time stress-cpu-hotplug.sh' down to 48s, close to classic. > > > > Woo-hoo!!! ;-) > > > > And thank you for your testing efforts! > > > > Should I be comparing this with the 55s number from your initial email, > > or to the 39s number? > > Should be the 39, but I'll get you a new tree vs classic number in this > same tree after I finish bisecting TSC going wonky. Sounds good!!! In theory, given 4-millisecond SRCU grace periods and 225,000 of them per run (estimated based on experience and on numbers you have already provided me), the 0x3ff should be worth only about one second of delay over the full test. On a really good day, I could probably invent some statistics to estimate the slowdown from the 50-microsecond cutoff, but today is not quite that good a day. And besides, the only difference between theory and practice is that in theory they are both the same. ;-) So I look forward to seeing your measurements! And best of everything with the wonky TSC!!! Thanx, Paul
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Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-26 00:40 +0200
Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-26 16:40 +0200
Re: TREE_SRCU slows hotplug by factor ~16 Mike Galbraith <efault@gmx.de> - 2017-04-26 17:30 +0200
Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-26 17:50 +0200
Re: TREE_SRCU slows hotplug by factor ~16 Mike Galbraith <efault@gmx.de> - 2017-04-26 18:00 +0200
Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-26 18:10 +0200
Re: TREE_SRCU slows hotplug by factor ~16 Mike Galbraith <efault@gmx.de> - 2017-04-26 19:50 +0200
Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-26 20:00 +0200
Re: TREE_SRCU slows hotplug by factor ~16 Mike Galbraith <efault@gmx.de> - 2017-04-26 20:20 +0200
Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-26 20:30 +0200
Re: TREE_SRCU slows hotplug by factor ~16 Mike Galbraith <efault@gmx.de> - 2017-04-27 05:50 +0200
Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-27 06:20 +0200
Re: TREE_SRCU slows hotplug by factor ~16 Mike Galbraith <efault@gmx.de> - 2017-04-27 06:20 +0200
Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-27 07:40 +0200
Re: TREE_SRCU slows hotplug by factor ~16 Mike Galbraith <efault@gmx.de> - 2017-04-27 07:50 +0200
Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-27 14:40 +0200
Re: TREE_SRCU slows hotplug by factor ~16 "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> - 2017-04-26 20:00 +0200
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