Hi all, I'm trying to figure out optimized code for some network drivers. I'm replacing certain APIs in the code and compare code for each API. To choose best optimized code, i need to first compile them and then disassemble the compiled code, where a change in single line would make a significant difference in the performance. So, my question is how to compile* x86 based network drivers on x86_64 Ubuntu machine*. Currently I'm running Ubuntu 14.04. Please help me out Thanks
On Tue, 07 Jun 2016 02:27:03 +0530, Shyam Saini said:
To choose best optimized code, i need to first compile them and then disassemble the compiled code, where a change in single line would make a significant difference in the performance.
Note that due to things like cache line misses, looking at the code will tell you almost nothing about which is *really* the "best" code...
So, my question is how to compile* x86 based network drivers on x86_64 Ubuntu machine*. Currently I'm running Ubuntu 14.04.
Why do you need to cross-compile? Just build the drivers as x86_64. Pretty much anybody who actually *cares* about performance has moved off 32-bit kernels a while ago (unless you're stuck with an embedded 32-bit CPU).
Note that due to things like cache line misses, looking at the code will tell you almost nothing about which is *really* the "best" code...
I thought of counting number of instructions in disassembled code for each case. Since I'm only replacing certain API's , rest of the code remains same. For example Replacing ACCESS_ONCE() API with READ_ONCE() Please correct me , if I'm wrong.
Why do you need to cross-compile? Just build the drivers as x86_64. Pretty much anybody who actually *cares* about performance has moved off 32-bit kernels a while ago (unless you're stuck with an embedded 32-bit CPU).
Earlier, whenever I run this command $ make drivers/staging/rdma/ I was getting this error CONFIG_X86_X32 enabled but no binutils support So, I thought to cross compile for x82. But now it seems i have solved by following this <http://stackoverflow.com/questions/12501124/errors-in-compiling-linux-kernel...> On Tue, Jun 7, 2016 at 3:16 AM, <Valdis.Kletnieks@vt.edu> wrote:
On Tue, 07 Jun 2016 02:27:03 +0530, Shyam Saini said:
To choose best optimized code, i need to first compile them and then disassemble the compiled code, where a change in single line would make a significant difference in the performance.
Note that due to things like cache line misses, looking at the code will tell you almost nothing about which is *really* the "best" code...
So, my question is how to compile* x86 based network drivers on x86_64 Ubuntu machine*. Currently I'm running Ubuntu 14.04.
Why do you need to cross-compile? Just build the drivers as x86_64. Pretty much anybody who actually *cares* about performance has moved off 32-bit kernels a while ago (unless you're stuck with an embedded 32-bit CPU).
participants (2)
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Shyam Saini -
Valdis.Kletnieks＠vt.edu