From mboxrd@z Thu Jan  1 00:00:00 1970
From: Zheng Li <dev@zheng.li>
Subject: Re: [PATCH v3 9/9] oxenstored: reduce syslog call
	overhead (fix typo)
Date: Fri, 26 Sep 2014 16:33:32 +0100
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To: Ian Jackson <Ian.Jackson@eu.citrix.com>
Cc: Dave Scott <Dave.Scott@citrix.com>, Joe Jin <joe.jin@oracle.com>, "Luis R. Rodriguez" <mcgrof@suse.com>, Luonengjun <luonengjun@huawei.com>, Fanhenglong <fanhenglong@huawei.com>, "Liuqiming (John)" <john.liuqiming@huawei.com>, xen-devel@lists.xenproject.org
List-Id: xen-devel@lists.xenproject.org

Hi Ian,

On 26/09/2014 16:16, Ian Jackson wrote:
> Zheng Li writes ("Re: [PATCH v3 9/9] oxenstored: reduce syslog call overhead (fix typo)"):
>> Setting up the TZ environment varialbe to avoid stat calls.
> ...
>> +		if not tz_is_set then Unix.putenv "TZ" ":/etc/localtime" in
>
> I wasn't aware of this syntax.  Can you point me to its specification ?

Please see the 3rd format (:characters format) in the linked document below

http://www.gnu.org/software/libc/manual/html_node/TZ-Variable.html

Also a similar issue reported on stackoverflow and discussion

http://stackoverflow.com/questions/4554271/how-to-avoid-excessive-stat-etc-localtime-calls-in-strftime-on-linux

I've manually tested the change. With TZ set, strace no longer shows the intensive stat calls, and the timestamps seem to be correct wrt the local time setting.

Cheers,
Zheng