[pushed] Add readahead cache to gdb's vFile:pread (Re: [PATCH 0/2] Better handling of slow remote transfers)

Pedro Alves
2015-08-21T09:34:39Z

On 08/20/2015 07:01 PM, Gary Benson wrote:
> Pedro Alves wrote:
>> Hey, that was a quick and dirty patch. :-)
>
> I know, no worries :)
>
>> Here's a cleaned up version. WDYT?
> [snip
>> This patch almost halves the time it takes to "target remote + run
>> to main" on a higher-latency connection.
>>
>> E.g., I've got a ping time of ~85ms to an x86-64 machine on the gcc
>> compile farm (almost 2000km away from me), and I'm behind a ~16Mbit
>> ADSL. When I connect to a gdbserver debugging itself on that machine
>> and run to main, it takes almost 55 seconds:
> [snip]
>> real 0m54.803s
>> user 0m0.329s
>> sys 0m0.064s
>>
>> While the readahead cache added by this patch, it drops to:
>>
>> real 0m29.462s
>> user 0m0.454s
>> sys 0m0.054s
>>
>> I added a few counters to show cache hit/miss, and got:
>>
>> readahead cache miss 142
>> readahead cache hit 310
>>
>> Tested on x86_64 Fedora 20.
>
> Very nice, please commit!

Pushed, master and 7.10.

Thanks,
Pedro Alves