Wireshark-dev: Re: [Wireshark-dev] tvb allocator (was: Re: [Wireshark-commits] master b6d20a2:
Hi All,
Please provide the input data for letting others reproduce the results
or perform the performance tests on pcap files already available to
the public.
I'm not a fan of implementing custom memory management methods because
partly because I highly doubt we can beat jemalloc easily on
performance and custom allocation methods can also have nasty bugs
like the one observed in OpenSSL:
http://www.tedunangst.com/flak/post/analysis-of-openssl-freelist-reuse
I wrote a short post about making all programs in Debian resistant to
malloc() related attacks using ASAN and wmem in its current form
prevents implementing the protection:
http://balintreczey.hu/blog/proposing-amd64-hardened-architecture-for-debian/
Please don't sacrifice protection for 2% speedup. Please keep wmem
usage for cases where it is used for garbage collecting (free() after
end of frame/capture file) not when the allocation and deallocation
are already done properly.
Thanks,
Balint
2014-07-11 8:58 GMT+02:00 Jakub Zawadzki <darkjames-ws@xxxxxxxxxxxx>:
> Hi,
>
> On Sat, Jun 21, 2014 at 10:12:48PM +0200, Jakub Zawadzki wrote:
>> If we're in topic of optimizing 'slower' [de]allocations in common functions:
>>
>> - tvb allocation/deallocation (2.5%, or 3.4% when no filtering)
>>
>> 243,931,671 * ???:tvb_new [/tmp/wireshark/epan/.libs/libwireshark.so.0.0.0]
>> 202,052,290 > ???:g_slice_alloc (2463493x) [/usr/lib64/libglib-2.0.so.0.3600.4]
>>
>> 291,765,126 * ???:tvb_free_chain [/tmp/wireshark/epan/.libs/libwireshark.so.0.0.0]
>> 256,390,635 > ???:g_slice_free1 (2435843x) [/usr/lib64/libglib-2.0.so.0.3600.4]
>
>> This, or next week I'll try to do tvb.
>
> ... or maybe this week:
>
> ver0 | 18,055,719,820 (-----------) | Base version 96f0585268f1cc4e820767c4038c10ed4915c12a
> ver1 | 18,185,185,838 (0.6% slower) | Change tvb allocator g_slice_* to wmem with file scope
> ver2 | 17,809,433,204 (1.4% faster) | Change tvb allocator g_slice_* to wmem with file/packet scope
> ver3 | 17,812,128,887 (1.3% faster) | Change tvb allocator g_slice_* to simple object allocator with epan scope
> ver4 | 17,704,132,561 (2.0% faster) | Change tvb allocator g_slice_* to simple object allocator with file scope
>
> I have uploaded patches & profiler outputs to: http://www.wireshark.org/~darkjames/tvb-opt-allocator/
>
> Please review, and check what version is OK to be applied.
>
>
> P.S: I'll might find some time to do ver5 with slab allocator, but it'll look like object allocator API with epan scope.
>
> Cheers,
> Jakub.
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