Re: [gentoo-dev] Manifest2 hashes, take n+1-th: 3 hashes for the tie-breaker case

[Joshua Kinard]

On 11/12/2017 22:48, Gordon Pettey wrote:
> On Sun, Nov 12, 2017 at 8:22 PM, Joshua Kinard <kumba@g.o> wrote:
>
>> Minor clarification, old single core //and// uni-processor.  Some older
>> machines have multiple physical CPUs that are single-core.  Threading
>> should be
>> okay on these, as long as the thread count stays under NR_CPUS.
>>
>> I also have a really old single-CPU system, MIPS (obviously).  Not the
>> fastest
>> on the block compared to the other equipment I've got, but does anyone
>> know of
>> any simple timing scripts/programs available that can benchmark some of
>> these
>> proposed digest hashes?  If they turn out to be reasonably quick on my old
>> machine, I doubt then that speed will be too much of an issue.
>>
>
> Even on your "old single-CPU MIPS" system, what percentage of time is
> spent verifying manifest hashes compared to actually building/installing?
> The whole "slow and/or multiple hashes will cause problems" argument
> seems specious.

It appears that you have misread my inquiry quite severely.  I am not terribly
interested in the whole argument of "multiple hashes" or "slow hashes".  It's
just my curiosity wanting to know if there's a reliable way to benchmark, on
the command line, several common/known digest hashing algorithms.  For my MIPS
systems, the type of CPU and system architecture is very different between each
machine.  Being able to compare between each of them might have uses down the road.

But also having a rough idea of how the actual hashes perform might also be of
use to the discussion.  Only to enlighten, not to push a particular side.

-- 
Joshua Kinard
Gentoo/MIPS
kumba@g.o
6144R/F5C6C943 2015-04-27
177C 1972 1FB8 F254 BAD0 3E72 5C63 F4E3 F5C6 C943

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