Memory allocation performance

Alexander Motin mav at mavhome.dp.ua
Wed Mar 5 20:56:25 UTC 2008


Bruce Evans wrote:
> Try profiling it one another type of CPU, to get different performance
> counters but hopefully not very different stalls.  If the other CPU doesn't
> stall at all, put another black mark against P4 and delete your copies of
> it :-).

I have tried to profile the same system with the same load on different 
hardware:
  - was Pentium4 2.8 at ASUS MB based on i875G chipset,
  - now PentiumD 3.0 at Supermicro PDSMi board based on E7230 chipset.

The results are completely different. The problem has gone:
         0.03     0.04  538550/2154375     ip_forward <cycle 1> [11]
         0.03     0.04  538562/2154375     em_get_buf [32]
         0.07     0.08 1077100/2154375     ng_package_data [26]
[15]1.8 0.14     0.15 2154375         uma_zalloc_arg [15]
         0.06     0.00 1077151/3232111     generic_bzero [22]
         0.03     0.00  538555/538555      mb_ctor_mbuf [60]
         0.03     0.00 2154375/4421407     critical_exit <cycle 2> [63]

         0.02     0.01  538554/2154376     m_freem [42]
         0.02     0.01  538563/2154376     mb_free_ext [54]
         0.04     0.03 1077100/2154376     ng_free_item [48]
[30]0.9 0.08     0.06 2154376         uma_zfree_arg [30]
         0.03     0.00 2154376/4421407     critical_exit <cycle 2> [63]
         0.00     0.01  538563/538563      mb_dtor_pack [82]
         0.01     0.00 2154376/4421971     critical_enter [69]

So probably it was some hardware related problem. First MB has video 
integrated to chipset without any dedicated memory, possibly it affected 
memory performance in some way. On the first system there were such 
messages on boot:
Mar  3 23:01:20 swamp kernel: acpi0: reservation of 0, a0000 (3) failed
Mar  3 23:01:20 swamp kernel: acpi0: reservation of 100000, 3fdf0000 (3) 
failed
Mar  3 23:01:20 swamp kernel: agp0: <Intel 82865G (865G GMCH) SVGA 
controller> on vgapci0
Mar  3 23:01:20 swamp kernel: agp0: detected 892k stolen memory
Mar  3 23:01:20 swamp kernel: agp0: aperture size is 128M
, can they be related?

-- 
Alexander Motin


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