From: Benjamin King <benjaminking@web.de>
To: Vince Weaver <vincent.weaver@maine.edu>
Cc: Milian Wolff <milian.wolff@kdab.com>, linux-perf-users@vger.kernel.org
Subject: Re: How to sample memory usage cheaply?
Date: Sat, 1 Apr 2017 18:27:38 +0200 [thread overview]
Message-ID: <20170401162738.GB8989@localhost> (raw)
In-Reply-To: <alpine.DEB.2.20.1704010952260.19001@macbook-air>
Hi Vince,
>> Also, the 'perf stat' output that I sent does not make much sense to me right
>> now. For example, when I add MAP_POPULATE to the flags for mmap, I only see
>> ~40 minor page faults, which I do not understand at all.
>
>have you tried accessing your file in random order? I think the kernel is
>likely doing some sort of readahead/prefetching. I think you can change
>that behavior with the madvise() syscall
No, I did not try that. Just reading in every 4096th byte. I did assume that
any way of populating the page table of my process would show up as a page
fault. I guess, I have to read a bit more on that...
Cheers,
Benjamin
next prev parent reply other threads:[~2017-04-01 16:27 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-30 20:04 How to sample memory usage cheaply? Benjamin King
2017-03-31 12:06 ` Milian Wolff
2017-04-01 7:41 ` Benjamin King
2017-04-01 13:54 ` Vince Weaver
2017-04-01 16:27 ` Benjamin King [this message]
2017-04-03 19:09 ` Benjamin King
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=20170401162738.GB8989@localhost \
--to=benjaminking@web.de \
--cc=linux-perf-users@vger.kernel.org \
--cc=milian.wolff@kdab.com \
--cc=vincent.weaver@maine.edu \
/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.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.