Increate zio write interrupt thread count.

Increasing the default zio_wr_int thread count from 8 to 16 improves
write performence by 13% on large systems.  More testing need to be
done but I suspect the ideal tuning here is ZTI_BATCH() with a minimum
of 8 threads.

diff --git a/module/zfs/spa.c b/module/zfs/spa.c
index 9365038..3599e61 100644 (file)
--- a/module/zfs/spa.c
+++ b/module/zfs/spa.c
@@ -106,7 +106,7 @@ const zio_taskq_info_t zio_taskqs[ZIO_TYPES][ZIO_TASKQ_TYPES] = {
        /* ISSUE        ISSUE_HIGH      INTR            INTR_HIGH */
        { ZTI_ONE,      ZTI_NULL,       ZTI_ONE,        ZTI_NULL },
        { ZTI_FIX(8),   ZTI_NULL,       ZTI_BATCH,      ZTI_NULL },
-       { ZTI_BATCH,    ZTI_FIX(5),     ZTI_FIX(8),     ZTI_FIX(5) },
+       { ZTI_BATCH,    ZTI_FIX(5),     ZTI_FIX(16),    ZTI_FIX(5) },
        { ZTI_FIX(100), ZTI_NULL,       ZTI_ONE,        ZTI_NULL },
        { ZTI_ONE,      ZTI_NULL,       ZTI_ONE,        ZTI_NULL },
        { ZTI_ONE,      ZTI_NULL,       ZTI_ONE,        ZTI_NULL },