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Re: Performance issue of -var-list-children on structs with many members and remote targets
- From: Yao Qi <yao at codesourcery dot com>
- To: Raphael Zulliger <zulliger at indel dot ch>, "gdb at sourceware dot org" <gdb at sourceware dot org>
- Date: Fri, 8 Aug 2014 18:31:20 +0800
- Subject: Re: Performance issue of -var-list-children on structs with many members and remote targets
- Authentication-results: sourceware.org; auth=none
- References: <53E47B59 dot 3060700 at indel dot ch>
On 08/08/2014 03:25 PM, Raphael Zulliger wrote:
> Now my simple question: Couldn't GDB be tweaked to get the struct member
> values by just one call (because members within a struct are guaranteed
> to be consecutive, aren't they?):
> 499,883 38-var-list-children var2.public
> 499,884 &"Sending packet: $m601050,24#??"
> I guess this would dramatically increase overall performance.
> I would really like to see such an improvement in GDB. Therefore, I'd be
> very happy to hear your thoughts and suggestion. Thinks like: What
> problems (e.g. border cases) could arise when implementing this? Where
> to start in the GDB code for such a modification? Or do there exist any
> GDB switches to improve performance on such operations? etc...
I have no idea how to merge multiple reads into one.
Cache is used in GDB to read code and stack from target, which
increases performance to some extent (See target_read_code and
target_read_stack). However, cache is NOT used to read general data.
Probably, you can make general data reading use cache too.