Re: 2.5.38-mm3

William Lee Irwin III
2002-09-26T12:42:44Z

On Thu, Sep 26, 2002 at 05:29:09AM -0700, William Lee Irwin III wrote:
>> Is there an update to the files_struct stuff too? I'm seeing large
>> overheads there also.

On Thu, Sep 26, 2002 at 06:10:52PM +0530, Dipankar Sarma wrote:
> files_struct_rcu is not in mm kernels, but I will upload the most
> recent version to the same download directory in LSE.
> I would be interested in fget() profile count change with that patch.

In my experience fget() is large even on UP kernels. For instance, a UP
profile from a long-running interactive load UP box (my home machine):

228542527 total 169.5902
216163353 default_idle 4503403.1875
850707 number 781.8998
829885 handle_IRQ_event 8644.6354
687351 proc_getdata 1227.4125
454401 system_call 8114.3036
446452 csum_partial_copy_generic 1800.2097
330157 tcp_sendmsg 76.4252
300022 vsnprintf 284.1117
271134 __generic_copy_to_user 3389.1750
237151 fget 3705.4844
222390 proc_pid_stat 308.8750
210759 fput 878.1625
186408 tcp_ioctl 314.8784
179146 sys_ioctl 238.2261
177419 do_softirq 1232.0764
167881 kmem_cache_free 1165.8403
154854 skb_clone 387.1350
149377 d_lookup 444.5744
139131 kmem_cache_alloc 668.8990
138638 kfree 866.4875
132555 sys_write 637.2837

This is only aggravated by cacheline bouncing on SMP. The reductions
of system cpu time will doubtless be beneficial for all.

Thanks,
Bill