From: Rich Felker <dalias@libc.org>
To: Alexey Izbyshev <izbyshev@ispras.ru>
Cc: musl@lists.openwall.com
Subject: Re: Draft outline of thread-list design
Date: Thu, 14 Feb 2019 18:19:36 -0500 [thread overview]
Message-ID: <20190214231936.GX23599@brightrain.aerifal.cx> (raw)
In-Reply-To: <20190214223224.GV23599@brightrain.aerifal.cx>
On Thu, Feb 14, 2019 at 05:32:24PM -0500, Rich Felker wrote:
> On Fri, Feb 15, 2019 at 12:16:39AM +0300, Alexey Izbyshev wrote:
> > In general, to my limited expertise, the design looks simple and
> > clean. I'm not sure whether it's worth optimizing to reduce
> > serialization pressure on pthread_create()/pthread_exit() because
> > creating a large amount of short-lived threads doesn't look like a
> > good idea anyway.
>
> Yes. One thing I did notice is that the window where pthread_create
> has to hold a lock to prevent new dlopen from happening is a lot
> larger than the window where the thread list needs to be locked, and
> contains mmap/mprotect. I think we should add a new "DTLS lock" here
> that's held for the whole time, with a protocol that if you need both
> the DTLS lock and the thread list lock, you take them in that order
> (dlopen would also need them both). This reduces the thread list lock
> window to just the __clone call and list update.
Also: the DTLS lock function can have a weak dummy, so that
static-linked programs don't even perform any locking.
Rich
next prev parent reply other threads:[~2019-02-14 23:19 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-12 18:26 Rich Felker
2019-02-12 20:23 ` Rich Felker
2019-02-14 21:16 ` Alexey Izbyshev
2019-02-14 22:32 ` Rich Felker
2019-02-14 22:54 ` Alexey Izbyshev
2019-02-14 23:19 ` Rich Felker [this message]
2019-02-15 0:20 ` Rich Felker
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190214231936.GX23599@brightrain.aerifal.cx \
--to=dalias@libc.org \
--cc=izbyshev@ispras.ru \
--cc=musl@lists.openwall.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://git.vuxu.org/mirror/musl/
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).