[3.0][GCD=ux0]When using sd2vita, sceIoMkdir becomes very slow

[blastrock]

I have made some tests on sceIoMkdir and I get the following results:

• sceIoOpen("ux0:somefile", SCE_O_CREAT|SCE_O_WRONLY) with or without sd2vita => 2ms
• sceIoMkdir("ux0:data", 06) or any folder that already exists => 2ms
• sceIoMkdir("ur0:test", 06) => 40ms
• sceIoMkdir("ux0:test", 06) without sd2vita and StorageMgr or gamesd => 40ms
• sceIoMkdir("ux0:test", 06) with sd2vita and StorageMgr or gamesd => 250 ms or more

This issue causes massive download speed drops in pkgj for games that contains hundreds of folders and eventually lead to a download failure due to HTTP timeout. I am also wondering if these 250ms aren't spent doing a FS sync to the sdcard which may wear it out sooner than necessary.

I tried a couple things (on the gamesd plugin, not this one, they are similar though). Replacing

static SceIoDevice uma_ux0_dev = { "ux0:", "exfatux0", "sdstor0:gcd-lp-ign-entire", "sdstor0:gcd-lp-ign-entire", MOUNT_POINT_ID };

with

static SceIoDevice uma_ux0_dev = { "ux0:", "exfatux0", "sdstor0:gcd-lp-ign-entire", NULL, MOUNT_POINT_ID };

Because that's what the structure looks like before being replaced. It did not help.

I also tried using sdstor0:gcd-lp-act-entire because that's a string that appears in the exfat kernel module.

Here is the small c++ snippet I used to benchmark mkdir:

void testmkdir(char const* path, int mode)
{
    sceIoRmdir(path);
    auto const start = std::chrono::high_resolution_clock::now();
    int err = sceIoMkdir(path, mode);
    auto const end = std::chrono::high_resolution_clock::now();
    auto const total =
            std::chrono::duration_cast<std::chrono::milliseconds>(end - start)
                    .count();

    if (err < 0)
        LOGF("sceIoMkdir({}, {:x}) time: {} failed: {:#08x}",
             path,
             mode,
             total,
             static_cast<uint32_t>(err));
    else
        LOGF("sceIoMkdir({}, {:x}) time: {} success", path, mode, total);
}

[CelesteBlue-dev]

Is ux0: the memcard or the SD2VITA ?
Maybe your microSD is slower than official memcards...

[blastrock]

ux0: is the sd2vita, or the internal memory, depending on the test. When it's the sd2vita it takes 250ms. The problem is specific to mkdir, so I don't think the issue is with the sd card. It also works fine when plugged in a computer.

[CelesteBlue-dev]

Happens in gamesd too (see xyzz/gamecard-microsd#30) so it is directly related to the way the sd2vita (GCD) patch is done.