From: Philippe Gerum <rpm@xenomai.org>
To: Qichen Qiu <ruiqurm@gmail.com>
Cc: xenomai@lists.linux.dev
Subject: Re: [Draft RFC] Bring POSIX signal to evl
Date: Fri, 20 Dec 2024 10:04:31 +0100 [thread overview]
Message-ID: <87ldwa4teo.fsf@xenomai.org> (raw)
In-Reply-To: <CAHR=ZXGvkXv1vEEitQmjY36xDT0D+s-SNVxW4a8CdD0RFxh1kQ@mail.gmail.com> (Qichen Qiu's message of "Fri, 20 Dec 2024 16:57:35 +0800")
Qichen Qiu <ruiqurm@gmail.com> writes:
> Hi.
> Thanks for your suggestions. It is really helpful.
>
>> However, big CAVEAT: the EVL/x4 locking model is fine-grained like the
>> one the regular kernel implements, unlike x3 which exhibits a single
>> coarse 'superlock'. Porting will require to reconsider a significant
>> portion of the original code under this new light.
>
> Do you mean the `nklock` that is used in almost every syscall? I wonder
> what the original purpose of this lock is. Is that a global lock like the BKL?
>
Yes, this is a recursive single lock coming from the Dark Ages, which is
basically used throughout the core to serialize access to almost all
resources. This is why x3 does not scale that well SMP-wise.
--
Philippe.
prev parent reply other threads:[~2024-12-20 9:04 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-12-18 12:26 [Draft RFC] Bring POSIX signal to evl Qichen Qiu
2024-12-19 14:31 ` Jan Kiszka
2024-12-20 8:46 ` Qichen Qiu
2024-12-19 15:43 ` Philippe Gerum
2024-12-20 8:59 ` Qichen Qiu
[not found] ` <CAHR=ZXGvkXv1vEEitQmjY36xDT0D+s-SNVxW4a8CdD0RFxh1kQ@mail.gmail.com>
2024-12-20 9:04 ` Philippe Gerum [this message]
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