zfs very poor performance compared to ufs due to lack of cache?

[Steven Hartland]

----- Original Message ----- 
From: "jhell" <jhell at DataIX.net>

> I am not exactly sure what your source is right now but guessing its at
> least 8.1-RELEASE & hoping its 8.1-STABLE.
> 
> Line 3656 & 3657 of arc.c ? what are they ?
> 
> Do they look like the following,
> 3656:  uint64_t available_memory = ptoa((uintmax_t)cnt.v_free_count
> 3657:      + cnt.v_cache_count);

Sorry yes running 8.1-RELEASE with the patches mentioned atm:

3656 of arc.c looks like:

    if (arc_size > arc_c_min) {
        uint64_t evictable_memory =
            arc_mru->arcs_lsize[ARC_BUFC_DATA] +
            arc_mru->arcs_lsize[ARC_BUFC_METADATA] +
            arc_mfu->arcs_lsize[ARC_BUFC_DATA] +
            arc_mfu->arcs_lsize[ARC_BUFC_METADATA];
        available_memory += MIN(evictable_memory, arc_size - arc_c_min);
    }

earlier at 3614 I have what I think your after which is:
    uint64_t available_memory = ptoa((uintmax_t)cnt.v_free_count);

    Regards
    Steve

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