From: "jistone at redhat dot com" <sourceware-bugzilla@sourceware.org>
To: systemtap@sources.redhat.com
Subject: [Bug kprobes/10839] kretprobes use excessive memory on x86_64 rawhide
Date: Mon, 26 Oct 2009 23:14:00 -0000 [thread overview]
Message-ID: <20091026231405.26651.qmail@sourceware.org> (raw)
In-Reply-To: <20091024022959.10839.jistone@redhat.com>
------- Additional Comments From jistone at redhat dot com 2009-10-26 23:14 -------
(In reply to comment #2)
> That's 37MB for a change of 100 maxactive, which comes to about 136 bytes each.
This waste is because kretprobes allocates each instance with a separate
kmalloc, which usually allocates more than actually requested.
global waste
probe kernel.trace("kmalloc") {
waste <<< ($bytes_alloc - $bytes_req)
}
probe timer.s(1) {
if (@count(waste))
printdln(" ", @count(waste), @sum(waste), @avg(waste))
delete waste
}
During KRETACTIVE=100, I get:
271 21949 80
281281 27015907 96
141 13280 94
During KRETACTIVE=200, I get:
25 2664 106
561746 53935824 96
127 12264 96
--
http://sourceware.org/bugzilla/show_bug.cgi?id=10839
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next prev parent reply other threads:[~2009-10-26 23:14 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-10-24 2:30 [Bug kprobes/10839] New: " jistone at redhat dot com
2009-10-25 8:01 ` [Bug kprobes/10839] " fche at redhat dot com
2009-10-26 23:07 ` jistone at redhat dot com
2009-10-26 23:14 ` jistone at redhat dot com [this message]
2009-10-29 17:02 ` [Bug translator/10839] KRETACTIVE should have a smaller default value jistone at redhat dot com
2009-10-30 12:12 ` fche at redhat dot com
2009-10-30 22:50 ` jistone at redhat dot com
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