This is the mail archive of the
systemtap@sourceware.org
mailing list for the systemtap project.
Re: [PATCH -tip v7 24/26] kprobes: Enlarge hash table to 4096 entries
- From: Andi Kleen <andi at firstfloor dot org>
- To: Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>
- Cc: linux-kernel at vger dot kernel dot org, Ingo Molnar <mingo at kernel dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Sandeepa Prabhu <sandeepa dot prabhu at linaro dot org>, Frederic Weisbecker <fweisbec at gmail dot com>, x86 at kernel dot org, Steven Rostedt <rostedt at goodmis dot org>, fche at redhat dot com, mingo at redhat dot com, systemtap at sourceware dot org, "H. Peter Anvin" <hpa at zytor dot com>, Thomas Gleixner <tglx at linutronix dot de>
- Date: Thu, 27 Feb 2014 13:45:48 -0800
- Subject: Re: [PATCH -tip v7 24/26] kprobes: Enlarge hash table to 4096 entries
- Authentication-results: sourceware.org; auth=none
- References: <20140227073315 dot 20992 dot 6174 dot stgit at ltc230 dot yrl dot intra dot hitachi dot co dot jp> <20140227073414 dot 20992 dot 16882 dot stgit at ltc230 dot yrl dot intra dot hitachi dot co dot jp>
Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> writes:
> Currently, since the kprobes expects to be used
> with less than 100 probe points, its hash table
> just has 64 entries. This is too little to handle
> several thousands of probes.
> Enlarge this to 4096 entires which just consumes
> 32KB (on 64bit arch) for better scalability.
32K for a debug feature that most systems never use seems
too large to me.
First can you check if smaller hash tables work too
(perhaps with a better hash, like jhash)
And then if you enlarge the table please allocate
it dynamically on the first use.
-Andi
--
ak@linux.intel.com -- Speaking for myself only