Re: [PATCH 3/3] object-store: use one oid_array per subdirectory for loose cache

From: René Scharfe <l.s.r@web.de>
Date: Jan 6, 2019, 22:58 UTC
Message-ID: <949fb568-295f-de4a-dc87-bc721e8aea29@web.de>
In-Reply-To: <87imz1ed25.fsf@evledraar.gmail.com>

Am 06.01.2019 um 21:38 schrieb Ævar Arnfjörð Bjarmason:

Show 16 quoted lines

>> $ git count-objects
>> 26733 objects, 68808 kilobytes
>>
>> Test                        HEAD^             HEAD
>> --------------------------------------------------------------------
>> 4205.1: log with %H         0.51(0.47+0.04)   0.51(0.49+0.02) +0.0%
>> 4205.2: log with %h         0.84(0.82+0.02)   0.60(0.57+0.03) -28.6%
>> 4205.3: log with %T         0.53(0.49+0.04)   0.52(0.48+0.03) -1.9%
>> 4205.4: log with %t         0.84(0.80+0.04)   0.60(0.59+0.01) -28.6%
>> 4205.5: log with %P         0.52(0.48+0.03)   0.51(0.50+0.01) -1.9%
>> 4205.6: log with %p         0.85(0.78+0.06)   0.61(0.56+0.05) -28.2%
>> 4205.7: log with %h-%h-%h   0.96(0.92+0.03)   0.69(0.64+0.04) -28.1%
> 
> Can you elaborate on the test setup required to get to the point where
> you got these numbers for subsequent comparison, i.e. how you generated
> the approx 100 objects per dir, what OS/version & storage type etc.

I happened to have that many loose objects lying around. Numbers are for Debian Testing on a Hyper-V VM on Windows 10 1893 on an SSD.

You could fake object directory entries with something like this:

    for d in .git/objects/??
    do
        for i in $(seq 0 9)
        do
            >"$d/0000000000000000000000000000000000000$i"
        done
    done

René