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Date:   Fri, 25 Mar 2022 12:02:09 +0100
From:   Cyril Hrubis <chrubis@suse.cz>
To:     Miklos Szeredi <miklos@szeredi.hu>
Cc:     Theodore Ts'o <tytso@mit.edu>,
        Christian Brauner <brauner@kernel.org>,
        Miklos Szeredi <mszeredi@redhat.com>,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        Linux API <linux-api@vger.kernel.org>,
        linux-man <linux-man@vger.kernel.org>,
        LSM <linux-security-module@vger.kernel.org>,
        Karel Zak <kzak@redhat.com>, Ian Kent <raven@themaw.net>,
        David Howells <dhowells@redhat.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <christian@brauner.io>,
        Amir Goldstein <amir73il@gmail.com>,
        James Bottomley <James.Bottomley@hansenpartnership.com>
Subject: Re: [RFC PATCH] getvalues(2) prototype
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Hi!
> > If so, have you benchmarked lsof using this new interface?
> 
> Not yet.  Looked yesterday at both lsof and procps source code, and
> both are pretty complex and not easy to plug in a new interface.   But
> I've not yet given up...

Looking at lsof it seems to use fopen() and fgets() to parse various
proc files. I doubt that we can make the parsing singificantly faster
without completely rewriting the internals.

As for procps the readproc.c has file2str() function that does copy
whole proc files into a buffer with open() - read() - close(). It may be
reasonably easy to hook the new systall there and it will probably make
ps and top slightly faster.

-- 
Cyril Hrubis
chrubis@suse.cz