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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] libxl: support for "rtc_timeoffset" and "localtime"
On Mon, Mar 19, 2012 at 9:22 AM, Lin Ming <mlin@xxxxxxxxxxxxx> wrote:
> On Mon, Mar 19, 2012 at 5:57 AM, Teck Choon Giam
> <giamteckchoon@xxxxxxxxx> wrote:
>> Hi Lin Ming,
>
> Hi Teck,
>
>>
>> Thanks for this patch. I am actually working to backport this patch
>> to xen-4.1-testing for self-testing. I have a question as below about
>> one of your code.
>>
>> On Sun, Mar 18, 2012 at 7:50 PM, Lin Ming <mlin@xxxxxxxxxxxxx> wrote:
>>> Implement "rtc_timeoffset" and "localtime" options compatible as xm.
>>>
>>> rtc_timeoffset is the offset between host time and guest time.
>>> localtime means to specify whether the emulted RTC appears as UTC or is
>>> offset by the host.
>>>
>>> Signed-off-by: Lin Ming <mlin@xxxxxxxxxxxxx>
>>> ---
>>> tools/libxl/libxl_dom.c | 3 +++
>>> tools/libxl/libxl_types.idl | 1 +
>>> tools/libxl/xl_cmdimpl.c | 13 +++++++++++++
>>> tools/libxl/xl_sxp.c | 1 +
>>> 4 files changed, 18 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/tools/libxl/libxl_dom.c b/tools/libxl/libxl_dom.c
>>> index 9b33267..0bdd654 100644
>>> --- a/tools/libxl/libxl_dom.c
>>> +++ b/tools/libxl/libxl_dom.c
>>> @@ -91,6 +91,9 @@ int libxl__build_pre(libxl__gc *gc, uint32_t domid,
>>> if (libxl_defbool_val(info->disable_migrate))
>>> xc_domain_disable_migrate(ctx->xch, domid);
>>>
>>> + if (info->rtc_timeoffset)
>>> + xc_domain_set_time_offset(ctx->xch, domid, info->rtc_timeoffset);
>>> +
>>> if (info->type == LIBXL_DOMAIN_TYPE_HVM) {
>>> unsigned long shadow;
>>> shadow = (info->shadow_memkb + 1023) / 1024;
>>> diff --git a/tools/libxl/libxl_types.idl b/tools/libxl/libxl_types.idl
>>> index 413a1a6..56f760c 100644
>>> --- a/tools/libxl/libxl_types.idl
>>> +++ b/tools/libxl/libxl_types.idl
>>> @@ -238,6 +238,7 @@ libxl_domain_build_info = Struct("domain_build_info",[
>>> ("target_memkb", MemKB),
>>> ("video_memkb", MemKB),
>>> ("shadow_memkb", MemKB),
>>> + ("rtc_timeoffset", uint32),
>>> ("disable_migrate", libxl_defbool),
>>> ("cpuid", libxl_cpuid_policy_list),
>>>
>>> diff --git a/tools/libxl/xl_cmdimpl.c b/tools/libxl/xl_cmdimpl.c
>>> index 1d59b89..b080a2b 100644
>>> --- a/tools/libxl/xl_cmdimpl.c
>>> +++ b/tools/libxl/xl_cmdimpl.c
>>> @@ -697,6 +697,19 @@ static void parse_config_data(const char
>>> *configfile_filename_report,
>>> }
>>> }
>>>
>>> + if (!xlu_cfg_get_long(config, "rtc_timeoffset", &l, 0))
>>> + b_info->rtc_timeoffset = l;
>>> +
>>> + if (!xlu_cfg_get_long(config, "localtime", &l, 0) && l) {
>>> + time_t t;
>>> + struct tm *tm;
>>> +
>>> + t = time(NULL);
>>> + tm = localtime(&t);
>>> +
>>> + b_info->rtc_timeoffset -= tm->tm_gmtoff;
>>
>> If tm->tm_gmtoff is 28800 for example (GMT +8) tested with
>> Asia/Singapore and Asia/Hong_Kong, then what is the
>> b_info->rct_timeoffset?
>> Is it b_info->rtc_timeoffset = b_info->rtc_timeoffset - tm->tm_gmtoff?
>> If this is so, then I guess it is not right. Shouldn't this be as
>> below instead?
>>
>> b_info->rtc_timeoffset += tm->tm_gmtoff;
>
> You are right.
>
> Python time.altzone/timezone is the offset in seconds "west" of UTC,
> while tm->tm_gmtoff is "east" of UTC.
I actually tested with the following summary for my backport patch
based on yours except the "b_info->rtc_timeoffset += tm->tm_gmtoff;"
to xen-4.1-testing and things look the same.
-----------------------------------------------------------------------------------
| Results | HVM domU config |
-----------------------------------------------------------------------------------
| xm | xl | localtime | rtc_timeoffset |
-----------------------------------------------------------------------------------
| same | same | Not Set | Not Set |
-----------------------------------------------------------------------------------
| same | same | Not Set | 0 |
-----------------------------------------------------------------------------------
| same | same | Not Set | 28800 |
-----------------------------------------------------------------------------------
| same | same | 0 | Not Set |
-----------------------------------------------------------------------------------
| same | same | 1 | Not Set |
-----------------------------------------------------------------------------------
>
> I just realized another problem: does ->tm_gmtoff already check
> DST(day light saving) zone?
This will need to ask those C experts... ... my testing didn't include
changing DST/tm_isdst = 1 though.
I tried to google about it and found
http://unix.derkeiler.com/Newsgroups/comp.unix.programmer/2004-07/0044.html
might be useful?
>
> Will check.
Thanks for your patch and prompt reply.
Kindest regards,
Giam Teck Choon
>
> Thanks,
> Lin Ming
>
>>
>> In python, time.altzone and time.timezone will return the offset with
>> negative for Asia or non-US/most of Western Europe depending it is
>> time.altzone or time.timezone according to
>> http://docs.python.org/library/time.html... someone correct me if I am
>> wrong :p
>>
>> Tested with python in Scientific Linux 6:
>>
>> Python 2.6.6 (r266:84292, Jan 4 2012, 16:09:22)
>> [GCC 4.4.6 20110731 (Red Hat 4.4.6-3)] on linux2
>> Type "help", "copyright", "credits" or "license" for more information.
>>>>> import time
>>>>> print time.altzone
>> -28800
>>>>> print time.timezone
>> -28800
>>>>> print time.tzname
>> ('SGT', 'SGT')
>>
>>
>> So unless tm->tm_gmtoff return the same value including negative as
>> python time function, then I am totally wrong and sorry about it.
>>
>> Thanks.
>>
>> Kindest regards,
>> Giam Teck Choon
>>
>>
>>> + }
>>> +
>>> if (!xlu_cfg_get_long (config, "videoram", &l, 0))
>>> b_info->video_memkb = l * 1024;
>>>
>>> diff --git a/tools/libxl/xl_sxp.c b/tools/libxl/xl_sxp.c
>>> index c68b6df..bb1f3da 100644
>>> --- a/tools/libxl/xl_sxp.c
>>> +++ b/tools/libxl/xl_sxp.c
>>> @@ -92,6 +92,7 @@ void printf_info_sexp(int domid, libxl_domain_config
>>> *d_config)
>>> printf("\t\t\t(firmware %s)\n", b_info->u.hvm.firmware);
>>> printf("\t\t\t(video_memkb %"PRId64")\n", b_info->video_memkb);
>>> printf("\t\t\t(shadow_memkb %"PRId64")\n", b_info->shadow_memkb);
>>> + printf("\t\t\t(rtc_timeoffset %"PRId32")\n",
>>> b_info->rtc_timeoffset);
>>> printf("\t\t\t(pae %s)\n",
>>> libxl_defbool_to_string(b_info->u.hvm.pae));
>>> printf("\t\t\t(apic %s)\n",
>>> libxl_defbool_to_string(b_info->u.hvm.apic));
>>> --
>>> 1.7.2.5
>>>
>>>
>>> _______________________________________________
>>> Xen-devel mailing list
>>> Xen-devel@xxxxxxxxxxxxx
>>> http://lists.xen.org/xen-devel
>>
>> _______________________________________________
>> Xen-devel mailing list
>> Xen-devel@xxxxxxxxxxxxx
>> http://lists.xen.org/xen-devel
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