ATA rman performance enhancement

From: Nate Lawson (nate_at_root.org)
Date: 01/03/05

  • Next message: Doug White: "Re: Hard system hangs on tty code (6-current)" 
    Date: Mon, 03 Jan 2005 09:45:09 -0800
To: sos@deepcore.dk

    While doing some benchmarking of other code, I noticed that there were a
    lot of calls to rman_get_bustag/handle(). They weren't taking up much
    actual time since they're pretty lightweight but seemed to be unnecessary.

    I worked up the attached diff and benchmarked it. There are about 1000
    calls a second to the rman routines without this patch and essentially
    none with it. It makes about a 1% difference in throughput under some
    IO loads. It is only for non-Promise or non-SII controllers right now
    since I didn't extend the initialization step to more than ata-pci.c.
    The same approach could be used for the other INW/OUTW calls as well but
    they're not in the fast path. I think it may make more of a difference
    with small reads.

    Feel free to test, cleanup, and commit.

    Thanks, 

    -- 
Nate

    Index: ata-all.h
    ===================================================================
    RCS file: /home/ncvs/src/sys/dev/ata/ata-all.h,v
    retrieving revision 1.87
    diff -u -r1.87 ata-all.h
    --- ata-all.h 9 Dec 2004 07:31:06 -0000 1.87
    +++ ata-all.h 3 Jan 2005 09:54:40 -0000
    @@ -331,6 +331,8 @@
     struct ata_resource {
         struct resource *res;
         int offset;
    + bus_space_tag_t tag;
    + bus_space_handle_t handle;
     };
     
     /* structure describing an ATA channel */
    @@ -493,7 +495,7 @@
                                            (offset), (addr), (count))
     
     #define ATA_IDX_INB(ch, idx) \
    - ATA_INB(ch->r_io[idx].res, ch->r_io[idx].offset)
    + bus_space_read_1(ch->r_io[idx].tag, ch->r_io[idx].handle, ch->r_io[idx].offset)
     
     #define ATA_IDX_INW(ch, idx) \
             ATA_INW(ch->r_io[idx].res, ch->r_io[idx].offset)
    @@ -514,13 +516,13 @@
             ATA_INSL_STRM(ch->r_io[idx].res, ch->r_io[idx].offset, addr, count)
     
     #define ATA_IDX_OUTB(ch, idx, value) \
    - ATA_OUTB(ch->r_io[idx].res, ch->r_io[idx].offset, value)
    + bus_space_write_1(ch->r_io[idx].tag, ch->r_io[idx].handle, ch->r_io[idx].offset, value)
     
     #define ATA_IDX_OUTW(ch, idx, value) \
             ATA_OUTW(ch->r_io[idx].res, ch->r_io[idx].offset, value)
     
     #define ATA_IDX_OUTL(ch, idx, value) \
    - ATA_OUTL(ch->r_io[idx].res, ch->r_io[idx].offset, value)
    + bus_space_write_4(ch->r_io[idx].tag, ch->r_io[idx].handle, ch->r_io[idx].offset, value)
     
     #define ATA_IDX_OUTSW(ch, idx, addr, count) \
             ATA_OUTSW(ch->r_io[idx].res, ch->r_io[idx].offset, addr, count)
    Index: ata-pci.c
    ===================================================================
    RCS file: /home/ncvs/src/sys/dev/ata/ata-pci.c,v
    retrieving revision 1.91
    diff -u -r1.91 ata-pci.c
    --- ata-pci.c 8 Dec 2004 11:17:38 -0000 1.91
    +++ ata-pci.c 3 Jan 2005 09:45:55 -0000
    @@ -417,15 +417,23 @@
     
         for (i = ATA_DATA; i <= ATA_STATUS; i ++) {
             ch->r_io[i].res = io;
    + ch->r_io[i].tag = rman_get_bustag(io);
    + ch->r_io[i].handle = rman_get_bushandle(io);
             ch->r_io[i].offset = i;
         }
         ch->r_io[ATA_ALTSTAT].res = altio;
    + ch->r_io[ATA_ALTSTAT].tag = rman_get_bustag(altio);
    + ch->r_io[ATA_ALTSTAT].handle = rman_get_bushandle(altio);
         ch->r_io[ATA_ALTSTAT].offset = ata_legacy(device_get_parent(dev)) ? 0 : 2;
         ch->r_io[ATA_IDX_ADDR].res = io;
    + ch->r_io[ATA_IDX_ADDR].tag = rman_get_bustag(io);
    + ch->r_io[ATA_IDX_ADDR].handle = rman_get_bushandle(io);
     
         if (ctlr->r_res1) {
             for (i = ATA_BMCMD_PORT; i <= ATA_BMDTP_PORT; i++) {
                 ch->r_io[i].res = ctlr->r_res1;
    + ch->r_io[i].tag = rman_get_bustag(ctlr->r_res1);
    + ch->r_io[i].handle = rman_get_bushandle(ctlr->r_res1);
                 ch->r_io[i].offset = (i - ATA_BMCMD_PORT)+(ch->unit * ATA_BMIOSIZE);
             }
         }

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  • Next message: Doug White: "Re: Hard system hangs on tty code (6-current)"