Re: [PATCH 0/8] workqueue: advance concurrency management
On Sat, Apr 20, 2013 at 2:11 AM, Tejun Heo wrote: > Hey, > > On Fri, Apr 19, 2013 at 06:10:57AM +0800, Lai Jiangshan wrote: >> Ping. > > Sorry, I've been at collab summit / lsf. Plus, it's a bit too late > for for-3.10 anyway. Anyways, after glancing over it, here are my > preliminary thoughts. The first one looks good but I'm not sure about > dropping nr_running adjustment. The only real benefit coming from > that is dropping a sched callback and if there's any performance / > overhead impact, I'm afraid it's gonna be negative. There are actual > benefits in using as few tasks as possible - waking_up() callback doesn't win too much in this. > the cache footprint gets smaller, cache footprint also be reduced in different way in the patchset. and memory atomic operations are reduced. > so unless there's a clear indication that the suggested Only simple. and remove the optimization from rare cases. > behavior is better in some way, I'm not sure what we're buying with > the proposed changes. > > 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 0/8] workqueue: advance concurrency management
On Sat, Apr 20, 2013 at 2:11 AM, Tejun Heo t...@kernel.org wrote: Hey, On Fri, Apr 19, 2013 at 06:10:57AM +0800, Lai Jiangshan wrote: Ping. Sorry, I've been at collab summit / lsf. Plus, it's a bit too late for for-3.10 anyway. Anyways, after glancing over it, here are my preliminary thoughts. The first one looks good but I'm not sure about dropping nr_running adjustment. The only real benefit coming from that is dropping a sched callback and if there's any performance / overhead impact, I'm afraid it's gonna be negative. There are actual benefits in using as few tasks as possible - waking_up() callback doesn't win too much in this. the cache footprint gets smaller, cache footprint also be reduced in different way in the patchset. and memory atomic operations are reduced. so unless there's a clear indication that the suggested Only simple. and remove the optimization from rare cases. behavior is better in some way, I'm not sure what we're buying with the proposed changes. 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 0/8] workqueue: advance concurrency management
Hey, On Fri, Apr 19, 2013 at 06:10:57AM +0800, Lai Jiangshan wrote: > Ping. Sorry, I've been at collab summit / lsf. Plus, it's a bit too late for for-3.10 anyway. Anyways, after glancing over it, here are my preliminary thoughts. The first one looks good but I'm not sure about dropping nr_running adjustment. The only real benefit coming from that is dropping a sched callback and if there's any performance / overhead impact, I'm afraid it's gonna be negative. There are actual benefits in using as few tasks as possible - the cache footprint gets smaller, so unless there's a clear indication that the suggested behavior is better in some way, I'm not sure what we're buying with the proposed changes. 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 0/8] workqueue: advance concurrency management
Hey, On Fri, Apr 19, 2013 at 06:10:57AM +0800, Lai Jiangshan wrote: Ping. Sorry, I've been at collab summit / lsf. Plus, it's a bit too late for for-3.10 anyway. Anyways, after glancing over it, here are my preliminary thoughts. The first one looks good but I'm not sure about dropping nr_running adjustment. The only real benefit coming from that is dropping a sched callback and if there's any performance / overhead impact, I'm afraid it's gonna be negative. There are actual benefits in using as few tasks as possible - the cache footprint gets smaller, so unless there's a clear indication that the suggested behavior is better in some way, I'm not sure what we're buying with the proposed changes. 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 0/8] workqueue: advance concurrency management
Ping. On Mon, Apr 15, 2013 at 12:41 AM, Lai Jiangshan wrote: > I found the early-increasing nr_running in wq_worker_waking_up() is useless > in many cases. it tries to avoid waking up idle workers for pending work item. > but delay increasing nr_running does not increase waking up idle workers. > > so we delay increasing and remove wq_worker_waking_up() and ... > > enjoy a simpler concurrency management. > > Lai Jiangshan (8): > workqueue: remove @cpu from wq_worker_sleeping() > workqueue: use create_and_start_worker() in manage_workers() > workqueue: remove cpu_intensive from process_one_work() > workqueue: quit cm mode when sleeping > workqueue: remove disabled wq_worker_waking_up() > workqueue: make nr_running non-atomic > workqueue: move worker->flags up > workqueue: rename ->nr_running to ->nr_cm_workers > > kernel/sched/core.c |6 +- > kernel/workqueue.c | 234 +++--- > kernel/workqueue_internal.h |9 +- > 3 files changed, 89 insertions(+), 160 deletions(-) > > -- > 1.7.7.6 > > -- > 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/ -- 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 0/8] workqueue: advance concurrency management
Ping. On Mon, Apr 15, 2013 at 12:41 AM, Lai Jiangshan la...@cn.fujitsu.com wrote: I found the early-increasing nr_running in wq_worker_waking_up() is useless in many cases. it tries to avoid waking up idle workers for pending work item. but delay increasing nr_running does not increase waking up idle workers. so we delay increasing and remove wq_worker_waking_up() and ... enjoy a simpler concurrency management. Lai Jiangshan (8): workqueue: remove @cpu from wq_worker_sleeping() workqueue: use create_and_start_worker() in manage_workers() workqueue: remove cpu_intensive from process_one_work() workqueue: quit cm mode when sleeping workqueue: remove disabled wq_worker_waking_up() workqueue: make nr_running non-atomic workqueue: move worker-flags up workqueue: rename -nr_running to -nr_cm_workers kernel/sched/core.c |6 +- kernel/workqueue.c | 234 +++--- kernel/workqueue_internal.h |9 +- 3 files changed, 89 insertions(+), 160 deletions(-) -- 1.7.7.6 -- 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/ -- 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/
[PATCH 0/8] workqueue: advance concurrency management
I found the early-increasing nr_running in wq_worker_waking_up() is useless in many cases. it tries to avoid waking up idle workers for pending work item. but delay increasing nr_running does not increase waking up idle workers. so we delay increasing and remove wq_worker_waking_up() and ... enjoy a simpler concurrency management. Lai Jiangshan (8): workqueue: remove @cpu from wq_worker_sleeping() workqueue: use create_and_start_worker() in manage_workers() workqueue: remove cpu_intensive from process_one_work() workqueue: quit cm mode when sleeping workqueue: remove disabled wq_worker_waking_up() workqueue: make nr_running non-atomic workqueue: move worker->flags up workqueue: rename ->nr_running to ->nr_cm_workers kernel/sched/core.c |6 +- kernel/workqueue.c | 234 +++--- kernel/workqueue_internal.h |9 +- 3 files changed, 89 insertions(+), 160 deletions(-) -- 1.7.7.6 -- 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/
[PATCH 0/8] workqueue: advance concurrency management
I found the early-increasing nr_running in wq_worker_waking_up() is useless in many cases. it tries to avoid waking up idle workers for pending work item. but delay increasing nr_running does not increase waking up idle workers. so we delay increasing and remove wq_worker_waking_up() and ... enjoy a simpler concurrency management. Lai Jiangshan (8): workqueue: remove @cpu from wq_worker_sleeping() workqueue: use create_and_start_worker() in manage_workers() workqueue: remove cpu_intensive from process_one_work() workqueue: quit cm mode when sleeping workqueue: remove disabled wq_worker_waking_up() workqueue: make nr_running non-atomic workqueue: move worker-flags up workqueue: rename -nr_running to -nr_cm_workers kernel/sched/core.c |6 +- kernel/workqueue.c | 234 +++--- kernel/workqueue_internal.h |9 +- 3 files changed, 89 insertions(+), 160 deletions(-) -- 1.7.7.6 -- 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/
