pcp
[Top] [All Lists]

Re: pmlogger -u questions

To: Ken McDonell <kenj@xxxxxxxxxxxxxxxx>
Subject: Re: pmlogger -u questions
From: "Frank Ch. Eigler" <fche@xxxxxxxxxx>
Date: Mon, 14 Apr 2014 19:18:20 -0400
Cc: Nathan Scott <nathans@xxxxxxxxxx>, pcp@xxxxxxxxxxx
Delivered-to: pcp@xxxxxxxxxxx
In-reply-to: <534C6531.6050502@xxxxxxxxxxxxxxxx>
References: <01e901cf56df$4ce97de0$e6bc79a0$@internode.on.net> <1665962954.4723287.1397437104781.JavaMail.zimbra@xxxxxxxxxx> <534B4330.1060008@xxxxxxxxxxxxxxxx> <y0meh104nvl.fsf@xxxxxxxx> <534C4FF4.5000304@xxxxxxxxxxxxxxxx> <20140414212551.GK14108@xxxxxxxxxx> <534C6531.6050502@xxxxxxxxxxxxxxxx>
User-agent: Mutt/1.4.2.2i
Hi -

On Tue, Apr 15, 2014 at 08:46:09AM +1000, Ken McDonell wrote:
> [...]
> Having actually made the change now, I like this even more ... in the 
> simplest implementation it is a one line change in __pmLogNewFile() to add
>     setvbuf(f, NULL, _IONBF, 0);

We should do a round of analysis (strace or stap or whatever) to see
how the change would affect i/o syscall traffic, just to confirm that
we write records in nice big chunks.  (If not, another possibility
would be to adjust the stdio buffering dynamically, based on the
actual size of the logger data records.)

- FChE

<Prev in Thread] Current Thread [Next in Thread>