Messages in this thread Patch in this message | | | Date | Sun, 2 Mar 2003 13:06:06 -0800 | From | William Lee Irwin III <> | Subject | Re: percpu-2.5.63-bk5-1 (properly generated) |
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At some point in the past, I wrote: >> make -j44 bzImage > /dev/null 304.02s user 122.14s system 1299% cpu 32.792 total [...]
On Sun, Mar 02, 2003 at 12:46:00PM -0800, Martin J. Bligh wrote: > How does that compare with and without your patch though?
There's a relatively large (12s/44s == 27%) difference between absolute timings on our machines, which suggests a large disturbance in the force. 2.5.63-bk5 virgin appears to get timings in the low 40's.
On Sun, Mar 02, 2003 at 12:46:00PM -0800, Martin J. Bligh wrote: > Would be useful if you can grab a before and after profile, and see exactly > what it is that's getting thrashed that you're fixing (may just be everything).
From the profile posted it's the division in page_zone().
-- wli
diff -urpN pernode-2.5.63-bk5-1/include/linux/mm.h pernode-2.5.63-bk5-2/include/linux/mm.h --- pernode-2.5.63-bk5-1/include/linux/mm.h 2003-03-02 02:55:14.000000000 -0800 +++ pernode-2.5.63-bk5-2/include/linux/mm.h 2003-03-02 12:55:20.000000000 -0800 @@ -316,6 +316,7 @@ static inline void put_page(struct page * sets it, so none of the operations on it need to be atomic. */ #define NODE_SHIFT 4 +#define ZONE_MASK ((1UL << NODE_SHIFT) - 1) #define ZONE_SHIFT (BITS_PER_LONG - 8) struct zone; @@ -324,7 +325,7 @@ DECLARE_PER_NODE(struct zone *[MAX_NR_ZO static inline struct zone *page_zone(struct page *page) { unsigned long zone = page->flags >> ZONE_SHIFT; - return per_node(zone_table, zone/MAX_NR_ZONES)[zone % MAX_NR_ZONES]; + return per_node(zone_table, zone >> NODE_SHIFT)[zone & ZONE_MASK]; } static inline void set_page_zone(struct page *page, unsigned long zone_num) diff -urpN pernode-2.5.63-bk5-1/mm/page_alloc.c pernode-2.5.63-bk5-2/mm/page_alloc.c --- pernode-2.5.63-bk5-1/mm/page_alloc.c 2003-03-02 02:55:14.000000000 -0800 +++ pernode-2.5.63-bk5-2/mm/page_alloc.c 2003-03-02 12:15:00.000000000 -0800 @@ -1262,7 +1262,7 @@ static void __init free_area_init_core(s */ for (i = 0; i < size; i++) { struct page *page = lmem_map + local_offset + i; - set_page_zone(page, nid * MAX_NR_ZONES + j); + set_page_zone(page, (nid << NODE_SHIFT) + j); set_page_count(page, 0); SetPageReserved(page); INIT_LIST_HEAD(&page->list); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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