Re: [RFC PATCH] greatly reduce SLOB external fragmentation

Pekka J Enberg
2008-01-10T10:55:16Z

Hi Matt,

On Thu, 10 Jan 2008, Pekka J Enberg wrote:
> I'll double check the results for SLUB next but it seems obvious that your
> patches are a net gain for SLOB and should be applied. One problem though
> with SLOB seems to be that its memory efficiency is not so stable. Any
> ideas why that is?

Ok, I did that. The number are stable and reproducible. In fact, the
average for SLUB is within 1 KB of the previous numbers. So, we have the
same .config, the same userspace, and the same hypervisor, so what's the
difference here?

We probably don't have the same version of GCC which perhaps affects
memory layout (struct sizes) and thus allocation patterns? I have included
ver_linux from my laptop here:

Linux haji 2.6.24-rc6 #21 SMP Thu Jan 10 12:30:59 EET 2008 i686 GNU/Linux

Gnu C 4.1.3
Gnu make 3.81
binutils 2.18
util-linux 2.13
mount 2.13
module-init-tools 3.3-pre2
e2fsprogs 1.40.2
reiserfsprogs 3.6.19
pcmciautils 014
PPP 2.4.4
Linux C Library 2.6.1
Dynamic linker (ldd) 2.6.1
Procps 3.2.7
Net-tools 1.60
Console-tools 0.2.3
Sh-utils 5.97
udev 113
wireless-tools 29
Modules Loaded af_packet ipv6 binfmt_misc rfcomm l2cap uinput radeon drm acpi_cpufreq cpufreq_userspace cpufreq_stats cpufreq_powersave cpufreq_ondemand freq_table cpufreq_conservative dock container joydev snd_intel8x0 snd_ac97_codec ac97_bus snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device pcmcia psmouse snd ipw2200 serio_raw pcspkr hci_usb soundcore snd_page_alloc bluetooth ieee80211 ieee80211_crypt yenta_socket rsrc_nonstatic pcmcia_core iTCO_wdt iTCO_vendor_support video output shpchp pci_hotplug intel_agp button agpgart thinkpad_acpi nvram evdev sg sd_mod ata_piix floppy ata_generic libata scsi_mod e1000 ehci_hcd uhci_hcd usbcore thermal processor fan fuse

Pekka