From: Thierry Delisle <tdelisle@uwaterloo.ca>
To: Peter Oskolkov <posk@google.com>
Cc: <posk@posk.io>, <avagin@google.com>, <bsegall@google.com>,
<jannh@google.com>, <jnewsome@torproject.org>,
<joel@joelfernandes.org>, <linux-api@vger.kernel.org>,
<linux-kernel@vger.kernel.org>, <mingo@redhat.com>,
<peterz@infradead.org>, <pjt@google.com>, <tglx@linutronix.de>,
Peter Buhr <pabuhr@uwaterloo.ca>
Subject: Re: [RFC PATCH 4/4 v0.3] sched/umcg: RFC: implement UMCG syscalls
Date: Mon, 19 Jul 2021 14:13:05 -0400 [thread overview]
Message-ID: <c8ea4892-51e5-0dc2-86c6-b705e8a23cde@uwaterloo.ca> (raw)
In-Reply-To: <CAPNVh5cmhFEWr4bmODkDDFhV=mHLcO0DZJ432GEL=OitzPP80g@mail.gmail.com>
> Latency/efficiency: on worker wakeup an idle server can be picked from
> the list and context-switched into synchronously, on the same CPU.
> Using FDs and select/poll/epoll will add extra layers of abstractions;
> synchronous context-switches (not yet fully implemented in UMCG) will
> most likely be impossible. This patchset seems much more efficient and
> lightweight than whatever can be built on top of FDs.
I can believe that.
Are you planning to support separate scheduling instances within a
single user
space? That is having multiple sets of server threads and workers can
only run
within a specific set.
I believe the problem with the idle_servers_ptr as specified is that it
is not
possible to reclaim used nodes safely. I don't see any indication of which
nodes the kernel can concurrently access and on which some memory
reclamation
scheme could be based.
What is the benefit of having users maintain themselves a list of idle
servers
rather than each servers marking themselves as 'out of work' and having the
kernel maintain the list?
next prev parent reply other threads:[~2021-07-19 18:42 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-07-16 18:47 [RFC PATCH 0/4 v0.3] sched/UMCG Peter Oskolkov
2021-07-16 18:47 ` [RFC PATCH 1/4 v0.3] sched: add WF_CURRENT_CPU and externise ttwu Peter Oskolkov
2021-07-16 18:47 ` [RFC PATCH 2/4 v0.3] sched/umcg: RFC: add userspace atomic helpers Peter Oskolkov
2021-07-16 18:47 ` [RFC PATCH 3/4 v0.3] sched/umcg: RFC: add userspace sll helpers Peter Oskolkov
2021-07-17 0:58 ` Thierry Delisle
2021-07-16 18:47 ` [RFC PATCH 4/4 v0.3] sched/umcg: RFC: implement UMCG syscalls Peter Oskolkov
2021-07-19 16:07 ` Thierry Delisle
2021-07-19 17:29 ` Peter Oskolkov
2021-07-19 18:13 ` Thierry Delisle [this message]
2021-07-19 19:46 ` Peter Oskolkov
2021-07-21 19:55 ` Thierry Delisle
2021-07-21 23:44 ` Peter Oskolkov
2021-07-23 19:06 ` Thierry Delisle
2021-07-26 16:44 ` Peter Oskolkov
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