Hi,
On 2021/9/9 下午8:45, Zhou Yanjie wrote:
Hi,
On 2021/9/8 下午8:41, Jiaxun Yang wrote:
在 2021/9/8 16:51, Thomas Bogendoerfer 写道:
On Wed, Sep 08, 2021 at 10:08:47AM +0800, 陈飞扬 wrote:
On Tue, 7 Sept 2021 at 21:49, Jiaxun Yang <jiaxun.yang@xxxxxxxxxxx>
wrote:
在 2021/9/7 14:16, FreeFlyingSheep 写道:
From: Feiyang Chen <chenfeiyang@xxxxxxxxxxx>
Convert mips syscall to use the generic entry infrastructure from
kernel/entry/*.
There are a few special things on mips:
- There is one type of syscall on mips32 (scall32-o32) and three
types
of syscalls on mips64 (scall64-o32, scall64-n32 and scall64-n64).
Now
convert to C code to handle different types of syscalls.
- For some special syscalls (e.g. fork, clone, clone3 and sysmips),
save_static_function() wrapper is used to save static registers. Now
SAVE_STATIC is used in handle_sys before calling do_syscall(), so
the
save_static_function() wrapper can be removed.
- For sigreturn/rt_sigreturn and sysmips, inline assembly is used to
jump to syscall_exit directly for skipping setting the error flag
and
restoring all registers. Now use regs->regs[27] to mark whether to
handle the error flag and always restore all registers in
handle_sys,
so these functions can return normally as other architecture.
Hmm, that would give us overhead of register context on these
syscalls.
I guess it's worthy?
Hi, Jiaxun,
Saving and restoring registers against different system calls can be
difficult due to the use of generic entry.
To avoid a lot of duplicate code, I think the overhead is worth it.
could you please provide numbers for that ? This code still runs
on low end MIPS CPUs for which overhead might mean a different
ballpark than some highend Loongson CPUs.
It shows ~3% regression for UnixBench on MT7621A (1004Kec).
+ Yanjie could you help with a run on ingenic platform?
Sure, I can help with JZ4775, JZ4780, X1000, X1830, X2000 from
Ingenic, and SF16A18, SF19A2890 from SiFlower.
Sorry for the delay.
I encountered some troubles when testing UNIX Bench on the Ingenic
X2000(SMT on) and two SiFlower processors,
so I ended up with only the following test results:
Score Without Patches Score With Patches Performance Change SoC
Model
105.9 101.2
-4.4% JZ4775
132.4 122.0
-7.9% JZ4780(SMP off)
170.2 149.5
-12.2% JZ4780(SMP on)
101.3 89.0
-12.1% X1000E
187.1 177.7
-5.0% X1830
324.9 312.2
-3.9% X2000(SMT off)
On the whole, the impact on performance is quite huge.
Thanks and best regards!
+ Paul could you help with a run on JZ4760 and JZ4770?
+ Nikolaus could you help with a run on JZ4730?
Thanks and best regards!
Thanks.
- Jiaxun
Thomas.
