From: Ming Lei <ming.lei@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Jens Axboe <axboe@kernel.dk>,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
Long Li <longli@microsoft.com>, Ingo Molnar <mingo@redhat.com>,
Keith Busch <keith.busch@intel.com>,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
John Garry <john.garry@huawei.com>,
Hannes Reinecke <hare@suse.com>
Subject: Re: [RFC PATCH 1/3] sched/core: add API for exporting runqueue clock
Date: Thu, 19 Dec 2019 09:29:14 +0800 [thread overview]
Message-ID: <20191219012914.GA6080@ming.t460p> (raw)
In-Reply-To: <20191218095101.GQ2844@hirez.programming.kicks-ass.net>
On Wed, Dec 18, 2019 at 10:51:01AM +0100, Peter Zijlstra wrote:
> On Wed, Dec 18, 2019 at 03:19:40PM +0800, Ming Lei wrote:
> > Scheduler runqueue maintains its own software clock that is periodically
> > synchronised with hardware. Export this clock so that it can be used
> > by interrupt flood detection for saving the cost of reading from hardware.
>
> But you don't have much, if any, guarantees the thing gets updated.
Any software clock won't be guaranteed to be updated in time, however,
they are still useful.
Thanks,
Ming
next prev parent reply other threads:[~2019-12-19 1:29 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-18 7:19 [RFC PATCH 0/3] softirq/blk-mq: implement interrupt flood detection for avoiding cpu lockup Ming Lei
2019-12-18 7:19 ` [RFC PATCH 1/3] sched/core: add API for exporting runqueue clock Ming Lei
2019-12-18 9:51 ` Peter Zijlstra
2019-12-19 1:29 ` Ming Lei [this message]
2019-12-19 9:20 ` Peter Zijlstra
2019-12-18 7:19 ` [RFC PATCH 2/3] softirq: implement interrupt flood detection Ming Lei
2019-12-18 10:49 ` Peter Zijlstra
2019-12-18 12:29 ` Peter Zijlstra
2019-12-19 1:59 ` Ming Lei
2019-12-19 9:23 ` Peter Zijlstra
2019-12-19 9:52 ` Ming Lei
2019-12-19 10:43 ` Daniel Wagner
2019-12-31 3:48 ` Ming Lei
2020-01-02 10:28 ` Daniel Wagner
2019-12-18 7:19 ` [RFC PATCH 3/3] blk-mq: complete request in rescuer process context in case of irq flood Ming Lei
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