Messages in this thread | | | Subject | Re: [RFC PATCH 0/4] Speed booting by sorting ORC unwind tables at build time | From | Shile Zhang <> | Date | Mon, 11 Nov 2019 10:44:29 +0800 |
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On 2019/11/8 17:25, Peter Zijlstra wrote: > On Fri, Nov 08, 2019 at 10:21:36AM +0100, Peter Zijlstra wrote: >> On Fri, Nov 08, 2019 at 09:42:55AM +0800, Shile Zhang wrote: >> >>>> Can sort{ex,orc}table() be ran concurrently? Do they want to be the same >>>> (threaded) tool? >>> I think it is possible to do those sort work concurrently, likes deferred >>> memory init which is big boot time speed up. >>> But I don't know if the exception table and ORC unwind tables can be >>> deferred, due to those tables might be used in early boot time, for early >>> exception handling and early debugging. I'm not familiar with that. >> I meant at link time, run both sorts concurrently such that we only have >> to wait for the longest, instead of the sum of them. >> >> They're not changing the same part of the ELF file, so it should be >> possible to have one tool have multiple threads, each sorting a >> different table. >> >> Aside from the .ex_table and ORC there's also .jump_table that wants >> sorting (see jump_label_sort_entries()). > Oh, and I'll be adding .static_call_sites soon, see: > > https://lkml.kernel.org/r/20191007082708.013939311@infradead.org > > (I should repost that) > > That gives us 4 tables to sort which we can do concurrently in 4 > threads.
I got your point now. I'll try to rework the sort tool to sort all tables concurrently in one tool with multiple-threads. Thanks for your advice!
>> I agree that doing it at link time makes sense, I just hate to do all >> this sorting in sequence and blowing up the link time. I don't build for >> customers, I build for single use boot and linking _SUCKS_.
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