From: Jens Axboe <axboe@kernel.dk>
To: Keith Busch <kbusch@kernel.org>
Cc: linux-block@vger.kernel.org, bvanassche@acm.org
Subject: Re: [PATCH 2/2] block/mq-deadline: fallback to per-cpu insertion buckets under contention
Date: Thu, 18 Jan 2024 11:28:41 -0700 [thread overview]
Message-ID: <322cdaa5-5d6c-43f9-92f4-08f8505896ae@kernel.dk> (raw)
In-Reply-To: <ZaltJ2H3pRVFqXIu@kbusch-mbp.dhcp.thefacebook.com>
On 1/18/24 11:25 AM, Keith Busch wrote:
> On Thu, Jan 18, 2024 at 11:04:57AM -0700, Jens Axboe wrote:
>> +#define DD_CPU_BUCKETS 32
>> +#define DD_CPU_BUCKETS_MASK (DD_CPU_BUCKETS - 1)
>
> A bit of wasted space on machines with < 32 CPUs, no? Sure, it's not
> much and the fixed size makes the implementation simpler, but these add
> up.
True, could make it allocated instead, 32 was just pulled out of thin
air. Might make sense to make the magic 8 or something instead, that's
probably Good Enough in general. Or we can make it dependent on the
number of online CPUs when initialized. Honestly just didn't want to
overcomplicate this initial RFC.
--
Jens Axboe
next prev parent reply other threads:[~2024-01-18 18:28 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-18 18:04 [PATCHSET RFC 0/2] mq-deadline scalability improvements Jens Axboe
2024-01-18 18:04 ` [PATCH 1/2] block/mq-deadline: serialize request dispatching Jens Axboe
2024-01-18 18:24 ` Bart Van Assche
2024-01-18 18:45 ` Jens Axboe
2024-01-18 18:51 ` Bart Van Assche
2024-01-18 18:55 ` Jens Axboe
2024-01-19 2:40 ` Ming Lei
2024-01-19 15:49 ` Jens Axboe
2024-01-18 18:04 ` [PATCH 2/2] block/mq-deadline: fallback to per-cpu insertion buckets under contention Jens Axboe
2024-01-18 18:25 ` Keith Busch
2024-01-18 18:28 ` Jens Axboe [this message]
2024-01-18 18:31 ` Bart Van Assche
2024-01-18 18:33 ` Jens Axboe
2024-01-18 18:53 ` Bart Van Assche
2024-01-18 18:56 ` Jens Axboe
2024-01-18 20:46 ` Bart Van Assche
2024-01-18 20:52 ` Jens Axboe
2024-01-19 23:11 ` Bart Van Assche
2024-01-18 19:29 ` [PATCHSET RFC 0/2] mq-deadline scalability improvements Jens Axboe
2024-01-18 20:22 ` Jens Axboe
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