Messages in this thread | | | Date | Wed, 22 Sep 1999 20:16:44 +0200 (CEST) | From | Andrea Arcangeli <> | Subject | Re: [patch] hashtable sizes for icache and dcache |
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On Wed, 22 Sep 1999 kernel@kvack.org wrote:
>considered an acceptable fix, even for the short term. Fix the problem, >not the symptoms.
You are wrong. I fixed the _cause_. My fix was a compile time thing so to make it working everywhere you should add a kernel option to set the new value or the old value. We all want it autotuning of course so it was a missing feature but the fix was correct.
To fix the _same_ cause in a dynamic way I should have changed my focus on a differen work, in a differen tree-branch and doing a controversial patch and so I choosed the compile time way since I only wanted to fix the problem on the class of machine I use (>=32mbyte of ram).
I am very happy to get the dynamic fix too of course and that's why I CC'ed to Chuck as I was almost sure he worked on something like that.
Now it cames out that the icache is static for everybody out there (unless Chuck did that), so I can do the icache dynamic thing of course, but in the meantime I'll __need__ to use the compile time fix to have a chance to test my code.
andrea@laser:~ > cat /proc/slabinfo | grep inode inode_cache 136909 136932 andrea@laser:~ > cat /proc/slabinfo | grep dentry dentry_cache 154681 155000
256 spurious_interrupt_bug 21.3333 724 __strncpy_from_user 20.1111 2023 do_anonymous_page 16.3145 759 system_call 13.5536 921 file_read_actor 12.1184 471 __udelay 7.8500 490 __generic_copy_from_user 7.6562 153 __get_user_1 7.6500 163 signal_return 6.7917 228 sock_mmap 6.3333 479 sock_poll 4.2768 41 coprocessor_error 3.4167 54 ret_with_reschedule 3.3750 410 unix_poll 2.5000 567 free_wait 2.4868 314 ide_config_drive_speed 2.4531 82 get_hardblocksize 2.2778 1654 do_select 2.2473 33 restore_all 2.2000 756 interruptible_sleep_on 2.0323 88 find_inode 1.6923 754 __get_free_pages 1.6391 308 d_lookup 1.4808
Without enlarging the hash the find_inode would be at the first hit with an huge value. Right now instead everything goes fine very fast and when the system will need memory the icache/dcache are shrunk automagically.
BTW, but I have not yet asked myself what the weird "spurious_interrupt_bug" at the top of the profiling is 8).
Andrea
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