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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-ia64-devel] [PATCH][RFC] performance tuning TAKE 7
Hi. These patches are for performance tuning TAKE 7
Theses patches are for the changeset of xen-ia64-unstable.hg
11701:2bfd19fc1b79c6a6712c99f875f1fbf883af3f35
>From dom0 <-> domU benchmark result and counter based analysis,
xen/ia64 tlb flush overhead is successfully reduced with these patches.
However domU network performance is still low.
There might another issues somewhere else, I guess.
I'll suspend further investigation and want to merge these patches.
Then I'll move to xen oprofile and tlb miss issue (including huge
page if possible). Merging these patches would be done as background task.
If necessary, I'll be back to network performance again later.
benchmark
=========
I did netperf benchmark very roughly by netperf -c -C -H <netserver> -l 100.
This is to see the effects very roughly.
The network environment isn't separeted from others,
only it was measured only once and it seems that the distribution of
netperf figures is large.
If you need an accurate benchmark result, you should measure sometimes
and get avarate by yourself. (and let me know!)
* environment
tiger4
CPU: 4packge x 2core x 2HT
Native: RHEL AS Release 4 Update 2: tiger4
dom0: tiger4, vcpu=4
domU: tiger4-g0, vcpu=8
NIC: e1000
em64t
CPU: Intel(R) Pentium(R) 4 CPU 3.60GHz stepping 0a
memory: 1GB
NIC: Tigon3 [partno(BCM95789) rev 4101 PHY(5750)]
* result
target <-> em64t(Mbits/sec)
target target -> em64t em64t -> target
netperf netserver nerperf netserver
Native 723.33 909.49
dom0(vanilla 11701) 673.96 836.05
dom0(patched) 675.75 837.75
domU(vanilla 11701) 136.28 77.78
domU(patched) 249.32 143.60
dom0 <-> domU in a same box (Mbits/sec)
domU -> dom0 dom0 -> domU
nerperf netserver netperf netserver
vanilla xen(C/S 11701) 576.71 329.49
patched 973.99 930.08
patches
=======
- performace counter
- p2m exposure
- per vcpu vhpt
- tlb tracking
- grant table transfer
- netback skbuff preregister
- netfront page preregister
- netback page preregister
- deferred page freeing
- tlb flush clock
- micro optimize __domain_flush_vtlb_track_entry
- supress clear_pages
patch detail
============
- per vcpu vhpt
It focuses on vcpu migration between physical cpus.
With credit scheduler, vcpu is heavily migrated.
This patch tries to reduce vTLB flush when vcpu is migrated.
- p2m exposure
DMA paravirtualization requires the conversion from pseudo physical address
to machine address. Currently it is done by hypercall.
This patch tries to reduce the conversion overhead by read-only
mapping the xen p2m table to domain.
- tlb tracking
It forcuses on grant table mapping.
When page is unmapped, full vTLB flush is necessary.
By tracking tlb insert on grant mapped page, full vTLB flush
can be avoided.
Especially vbd does only DMA, so dom0 doesn't insert tlb entry
on the grant mapped page. In such case any vTLB flush isn't needed.
- netback skbuff/netfront/netback page tlb tracking
This focuses on grant table transfer.
When page is transfered, full vTLB flush is necessary on both
sender domain and receiver domain.
By preregistering the page, Xen/IA64 begins to track tlb insert on
regestered pages.
- deferred page freeing
When the page in which tlb insert isn't tracked is unmapped/zapped from
domain, full vTLB flush is necessary again.
Balloon driver and grant table page transfer is the case.
This patch focuses on it.
It tries to batch freeing/zapping page from domain in order
to reduce full vTLB flush.
modifies tlb track page hypercall semantics and
reimplements tlb untrack page hypercall.
This patch tries to reduce vTLB flush cost of
tlb track/untrack/zap page hypercall by trying to batch using timer.
- tlb flush clock
This is intended to be a counter part of Xen/x86 tlb flush clock.
But this is used only when vcpu context switch only. not for lazy tlb flush.
included patches
================
11457:de77bfdecfbe_avoid_long_time_interrupt_masking.patch
11458:2bf4fc5ee839_perfc_for_vtlb_flush.patch
11459:dc1c8c91d249_perfc_mm_c.patch
11460:edbfec69d631_perfc_dom0vp_p2m_and_m2p.patch
11461:357d5479c0ff_p2m_exposure_xen_side.patch
11462:dde3a660f354_p2m_exposure_linux_side.patch
11463:1ae54e6b7ac9_p2m_exposure_test_module.patch
11464:065b48a99038_script_for_p2m_test_module.patch
11465:96b229487ae2_pervcpu_vhpt.patch
11466:da72199ba08c_fix_pte_flags_conflict.patch
11467:677fdf7aa2de_import_linux_hash.h.patch
11468:114c67d3d090_tlb_track.patch
11469:c5fde1737a9b_deferred_page_freeing.patch
11470:e123f0373d66_skbuff_tlb_tracking_xen_side.patch
11471:1313603b6f82_skbuff_tlb_tracking_linux_side.patch
11472:14a194e7caa9_tlb_track_netfront_page_xen_side.patch
11473:31a91097ca2b_tlb_tracking_on_netfront_page_linux_side.patch
11474:644d8aa4ce8f_tlbflush_clock.patch
11475:3debc96c950d_tlb_zap_page_hypercall_xen_side.patch
11476:a276174da6dd_tlb_zap_hypercall_linux_side.patch
FWIW my dot configs are as follows
- xen dot config
crash_debug=y
debug=y
verbose=y
xen_ia64_dom0_virtual_physical=y
xen_ia64_tlb_track=y
#xen_ia64_tlb_track_cnt=y
xen_ia64_tlb_track_cnt=n
xen_ia64_tlb_track_grant_table_page_transfer=y
xen_ia64_tlb_track_skbuff=y
xen_ia64_tlb_track_netfront_page=y
xen_ia64_tlb_track_deferred_flush=y
xen_ia64_pervcpu_vhpt=y
xen_ia64_deferred_free=y
xen_ia64_tlbflush_clock=y
xen_ia64_tlbflush_clock_tlb_track_entry=y
xen_ia64_clear_page=n
perfc=y
perfc_arrays=y
- Linux dot config includes
CONFIG_XEN_IA64_VDSO_PARAVIRT=y
CONFIG_XEN_IA64_EXPOSE_P2M=y
CONFIG_XEN_IA64_EXPOSE_P2M_USE_DTR=y
CONFIG_XEN_IA64_TLB_TRACK_SKBUFF=y
CONFIG_XEN_IA64_TLB_TRACK_NETFRONT_PAGE=y
CONFIG_XEN_IA64_TLB_TRACK_NETBACK_PAGE=y
thanks.
--
yamahata
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