Thank you very much for the advice. I will try __gcov_dump first.
Yuan
2015-06-02 12:14 GMT+08:00 Xinliang David Li :
> Using AutoFDO is one way. For PGO, you may want to to try using
> __gcov_dump interface to explicitly control the timing and order of
> the profile dump --- i.e., invoke __gcov_
Hi,
I am trying PGO on Nginx, which has a main process and several worker processes.
I find that the collected profile data files only contain information
for the main process, which is probably a data race (the main process
exits immediately after worker processes exit).
How can I solve this prob
Actually GCC does not help reduce branch misprediction rate on modern
X86 processors.
Reducing branch taken rate is more important.
Related discussion: https://gcc.gnu.org/ml/gcc/2014-12/msg0.html
Yuan
2015-01-13 22:13 GMT+08:00 :
> Depending on what the processor hardware can do, the data y
Thank you for the explanation!
I tried the following simple code:
int test(int k)
{
int x = 0;
for (int i = 0; i < k; ++i)
x += i;
return x;
}
It was compiled (-O2) to something like:
int test(int k)
{
if (k == 0) goto ret0;
int x = 0;
int i = 0;
loop:
x += i;
i += 1;
if (i
Hi,
I have analyzed the branch taken rate of the Linux kernel compiled
with GCC (using localyesconfig from Debian config) and found something
strange.
Hardware: Intel Core i7-4770, 32G RAM, 10GbE
Software: Linux 3.16.7, GCC 4.9.3 20121201, Debian sid
I use perf with rbf88:k,rff88:k events (Haswe
2014-12-01 17:50 GMT+08:00 Kyrill Tkachov :
>> In https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html , the
>> description of option `-freorder-blocks' says `in order to reduce
>> number of taken branches and improve code locality'. It is confusing.
>> When will the `and' condition happen? Tha
Hi,
In https://gcc.gnu.org/onlinedocs/gcc/Optimize-Options.html , the
description of option `-freorder-blocks' says `in order to reduce
number of taken branches and improve code locality'. It is confusing.
When will the `and' condition happen? That is, taken branches reduced
AND code locality impr
