From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tao Ma Date: Wed, 05 Jan 2011 10:25:17 +0800 Subject: [Ocfs2-devel] [PATCH 00/34] OCFS2: Add trace event and replace mlog(0). In-Reply-To: <20110104221517.GB30671@mail.oracle.com> References: <4D12F7E7.1090204@tao.ma> <20101231125217.GC21179@mail.oracle.com> <4D1DF2A3.9090106@tao.ma> <20101231223951.GC20521@mail.oracle.com> <4D22E32D.40406@tao.ma> <20110104221517.GB30671@mail.oracle.com> Message-ID: <4D23D68D.7040809@tao.ma> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ocfs2-devel@oss.oracle.com On 01/05/2011 06:15 AM, Joel Becker wrote: > On Tue, Jan 04, 2011 at 05:06:53PM +0800, Tao Ma wrote: >> On 01/01/2011 06:39 AM, Joel Becker wrote: >>> On Fri, Dec 31, 2010 at 11:11:31PM +0800, Tao Ma wrote: >>>> On 12/31/2010 08:52 PM, Joel Becker wrote: >>>>> Overall this seems pretty straightforward. There wasn't a lot >>>>> of editing of masklog entries; we still have a million tracepoints. I >>>>> wonder how much memory that will use. Have you checked the space usage >>>>> of all the sysfs files for all of our tracepoints? >>>> Sorry, I don't know how to check the space usage of these files. any tips? >>> >>> Just count the number of files and directories added to sysfs. >>> I believe the files disappear when not open, but the directories >>> I think have inode and dentry structures around permanently.. >> OK, so >> #find /sys/kernel/debug/tracing/events/ocfs2 -type d|wc -l >> give me 319. Every trace event dir has 4 >> members(enable,filter,format and id). So it contains about >> 1600(dir+files). > > I think what matters to count is dirs, because files disappear > when you're not using them. > If you have 319 trace event directories, that's 319 inodes. On > my x86, a vanilla struct inode is 360 bytes and a dentry is 136 bytes. > That's 154K always in RAM for these knobs. I gotta say that I'm not too > worried about 154K. On x86_64 (ca-build24) this grows to 241K. I > imagine it will double when cluster and dlm are moved to similar trace > events. > Are we OK with 300K on x86 and 500K on x86_64 always used up by > these tracing entries? yeah, it isn't much I guess. And for ext4, yes, it has a small number because they have a very limited debug tracing than us, maybe because they evolved from ext2->ext3->ext4. So the code base is really stable now. And I guess we can remove some of the trace events if we feel that the code is stable enough. ;) Regards, Tao