Re: [PATCH v5 1/3] perf: add PERF_RECORD_NAMESPACES to include namespaces related info

[Hari Bathini <hbathini@linux.vnet.ibm.com>]

Hi Peter,


On Wednesday 18 January 2017 07:56 PM, Peter Zijlstra wrote:
> On Tue, Jan 17, 2017 at 07:47:22PM +0530, Hari Bathini wrote:
>> With the advert of container technologies like docker, that depend
>> on namespaces for isolation, there is a need for tracing support for
>> namespaces. This patch introduces new PERF_RECORD_NAMESPACES event
>> for tracing based on namespaces related info.
> This fails to mention the whole namespace of namespaces issue Eric

IIUC, Eric wanted to have device info saved for each namespace separately
to avoid the need for a namespace of namespaces in future.

> brought up. Where are we on that, and or why isn't it required?


I did address that in v4 and haven't changed it in v5.
I am not sure if it needs any mentioning in the changelog..

>> +/*
>> + * The maximum size of the name of each namespace
>> + */
>> +#define NS_NAME_SIZE				8
>> +
>> +struct perf_ns_link_info {
>> +	char	name[NS_NAME_SIZE];
> Do we really need a name? why?

Helps print new namespaces info along with name without any changes in
perf tool. Avoids hard-coding names too..

Thanks
Hari