New optimized soreceive_stream() for TCP sockets, proof of concept

[John Baldwin]

On Monday 05 March 2007 15:43, Andrew Gallatin wrote:
> 
> John Baldwin writes:
>  > > John has a patch that pins interrupt threads, etc, not sure what the 
status 
>  > of 
>  > > that is.  CC'd.
>  > 
>  > Tested and around for over a year.  Sent to people several times but no 
>  > benchmarking has resulted.  It lives in p4 in //depot/user/jhb/intr/...
>  > 
>  > I've just regenerated the patch at 
>  > http://www.FreeBSD.org/~jhb/patches/intr_bind.patch (same URL as the last 
N 
> 
> It seems very useful, in conjunction with some sort of CPU binding
> API.  With ULE, and netserver bound via a hack to CPU 1, I
> can nearly double the bandwidth by binding my ithread
> to the opposite CPU using your patch.
> 
> BTW, you need a little sanity checking somehere in the API
> I tried to remove binding, and guessed at binding to -1 rather
> than reading the source.  That resulted in this panic:
> 
> # ./ibind/ibind 256 -1
> kernel trap 12 with interrupts disabled
> 
> 
> Fatal trap 12: page fault while in kernel mode
> cpuid = 1; apic id = 01
> fault virtual address   = 0x3806778bc
> fault code              = supervisor read data, page not present
> instruction pointer     = 0x8:0xffffffff8040a509
> stack pointer           = 0x10:0xffffffff91e88ad0
> frame pointer           = 0x10:0xffffffff91e88b00
> code segment            = base 0x0, limit 0xfffff, type 0x1b
>                         = DPL 0, pres 1, long 1, def32 0, gran 1
> processor eflags        = resume, IOPL = 0
> current process         = 788 (ibind)
> [thread pid 788 tid 100047 ]
> Stopped at      intr_bind+0xe9: movl    cpu_apic_ids(,%rdi,4),%esi
> db> bt
> Tracing pid 788 tid 100047 td 0xffffff001ea1b840
> intr_bind() at intr_bind+0xe9
> sysarch() at sysarch+0x14a
> ia32_syscall() at ia32_syscall+0x236
> Xint0x80_syscall() at Xint0x80_syscall+0x60
> 
> Thanks again!

There's currently no way to remove binding, and yes, the interface is a bit 
rough.  We need a way for userland to query the current state for example.
And I really think we might need to provide an MI interface with an MD 
callback.

-- 
John Baldwin