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Re: [Bug kprobes/2666] List active probes
- From: "James Dickens" <jamesd dot wi at gmail dot com>
- To: sourceware-bugzilla at sourceware dot org
- Cc: systemtap at sources dot redhat dot com
- Date: Tue, 16 Jan 2007 09:55:28 -0600
- Subject: Re: [Bug kprobes/2666] List active probes
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- References: <20060516165627.2666.jkenisto@us.ibm.com> <20070116130920.22925.qmail@sourceware.org>
On 16 Jan 2007 13:09:20 -0000, srinivasa at in dot ibm dot com
<sourceware-bugzilla@sourceware.org> wrote:
------- Additional Comments From srinivasa at in dot ibm dot com 2007-01-16 13:09 -------
(In reply to comment #2)
> any idea how the system will respond when there are 40,000 active
> probes or more?
>
> James Dickens
> uadmin.blogspot.com
>
>
Eventhough I haven't tested the patch for 40,000 active probes, size of
/proc/kprobes/list file depends on available memory and maximum size of the
proc file.
i was thinking about the time spent in
+ preempt_disable();
+ hlist_for_each_entry_rcu(p, node, head, hlist) {
+ sym = kallsyms_lookup((unsigned long)p->addr, &size,
+ &offset, &modname, namebuf);
+ if (p->pre_handler == aggr_pre_handler) {
+ list_for_each_entry_rcu(kp, &p->list, list)
+ report_probe(pi, kp, sym, offset, modname);
+ } else
+ report_probe(pi, p, sym, offset, modname);
+ }
+ preempt_enable();
with preemption disabled... it could a second or more, if many probes
are enabled, it could have a negative effect on a production server.
James
--
http://sourceware.org/bugzilla/show_bug.cgi?id=2666
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