user/sven/linux.git/arch/mips/lib/csum_partial.S, branch leds/master

MIPS: csum_partial: Improve instruction parallelism.

2015-04-01T15:22:11Z

Computing sum introduces true data dependency. This patch removes some true data depdendencies, hence increases instruction level parallelism. This patch brings up to 50% csum performance gain on Loongson 3a. One example about how this patch works is in CSUM_BIGCHUNK1: // ** original ** vs ** patch applied ** ADDC(sum, t0) ADDC(t0, t1) ADDC(sum, t1) ADDC(t2, t3) ADDC(sum, t2) ADDC(sum, t0) ADDC(sum, t3) ADDC(sum, t2) In the original implementation, each ADDC(sum, ...) depends on the sum value updated by previous ADDC(as source operand). With this patch applied, the first two ADDC operations are independent, hence can be executed simultaneously if possible. Another example is in the "copy and sum calculating chunk": // ** original ** vs ** patch applied ** STORE(t0, UNIT(0) ... STORE(t0, UNIT(0) ... ADDC(sum, t0) ADDC(t0, t1) STORE(t1, UNIT(1) ... STORE(t1, UNIT(1) ... ADDC(sum, t1) ADDC(sum, t0) STORE(t2, UNIT(2) ... STORE(t2, UNIT(2) ... ADDC(sum, t2) ADDC(t2, t3) STORE(t3, UNIT(3) ... STORE(t3, UNIT(3) ... ADDC(sum, t3) ADDC(sum, t2) With this patch applied, ADDC and the **next next** ADDC are independent. Signed-off-by: chenj Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/9608/ Signed-off-by: Ralf Baechle

MIPS: Use WSBH/DSBH/DSHD on Loongson 3A

2014-09-22T11:35:46Z

Signed-off-by: chenj Cc: linux-mips@linux-mips.org Cc: chenhc@lemote.com Patchwork: https://patchwork.linux-mips.org/patch/7542/ Patchwork: https://patchwork.linux-mips.org/patch/7550/ Signed-off-by: Ralf Baechle

MIPS: csum_partial.S CPU_DADDI_WORKAROUNDS bug fix

2014-05-12T22:29:39Z

This change reverts most of commit 60724ca59eda766a30be57aec6b49bc3e2bead91 [MIPS: IP checksums: Remove unncessary .set pseudos] that introduced warnings with the CPU_DADDI_WORKAROUNDS option set: arch/mips/lib/csum_partial.S: Assembler messages: arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:467: Warning: used $3 with ".set at=$3" [...] arch/mips/lib/csum_partial.S:577: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:577: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:577: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3" arch/mips/lib/csum_partial.S:601: Warning: used $3 with ".set at=$3" [and so on, and so on...] The warnings are benign and good code is produced regardless because no macros that'd use the assembler's temporary register are involved, however the `.set noat' directives removed by the commit referred are crucial to guarantee this is still going to be the case after any changes in the future. Therefore they need to be brought back to place which this change does. Signed-off-by: Maciej W. Rozycki Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/6686/ Signed-off-by: Ralf Baechle

MIPS: lib: csum_partial: Add EVA support

2014-03-26T22:09:17Z

Use EVA specific functions to read and write data to user address space. Signed-off-by: Markos Chandras

MIPS: lib: csum_partial: Add macro to build csum_partial symbols

2014-03-26T22:09:17Z

In preparation for EVA support, we use a macro to build the __csum_partial_copy_user main code so it can be shared across multiple implementations. EVA uses the same code but it replaces the load/store/prefetch instructions with the EVA specific ones therefore using a macro avoids unnecessary code duplications. Signed-off-by: Markos Chandras

MIPS: lib: csum_partial: Merge EXC and load/store macros

2014-03-26T22:09:17Z

Each load/store macro always adds an entry to the __ex_table using the EXC macro. There are cases where a load instruction may never fail such as when we are sure the load happens in the kernel address space. Therefore, we merge these the EXC and LOADX/STOREX macros into a single one. We also expand the argument list in the EXC macro to make the macro more flexible. The extra 'type' argument is not used by this commit, but it will be used when EVA support is added to memcpy. Signed-off-by: Markos Chandras

MIPS: checksum: Split the 'copy_user' symbol

2014-03-26T22:09:17Z

The 'copy_user' symbol can be used to copy from or to userland so we will use two different symbols for these operations. This makes no difference in the existing code, but when the core is operating in EVA mode, different instructions need to be used to read and write to userland address space. The old function has also been renamed to 'copy_kernel' to denote that it is suitable for copy data to and from kernel space. Signed-off-by: Markos Chandras

MIPS: Use CONFIG_CPU_MIPSR2 in csum_partial.S

2013-03-12T09:18:18Z

The csum_partial implementation contain optimalizations for the MIPS R2 instruction set. This optimization is never enabled however because the if directive uses the CPU_MIPSR2 constant which is not defined anywhere. Use the CONFIG_CPU_MIPSR2 constant instead. Signed-off-by: Gabor Juhos Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/4971/ Signed-off-by: Ralf Baechle

MIPS: Whitespace cleanup.

2013-02-01T09:00:22Z

Having received another series of whitespace patches I decided to do this once and for all rather than dealing with this kind of patches trickling in forever. Signed-off-by: Ralf Baechle

MIPS: IP checksums: Optimize adjust of sum on buffers of odd alignment.

2008-10-11T15:18:53Z

Signed-off-by: Ralf Baechle