Re: Can't trace any sendfile system call from Kafka process

Hi Ming,

Maybe this ticket could be useful to you:
https://issues.apache.org/jira/browse/KAFKA-7504


Guozhang

On Fri, Aug 28, 2020 at 8:21 AM Ming Liu <mingaliu@gmail.com> wrote:

> Hi
> One major reason that Kafka is fast is because it is using sendfile()
> for zero copy, as what it described at
> https://kafka.apache.org/documentation/#producerconfigs,
>
> This combination of pagecache and sendfile means that on a Kafka
> cluster where the consumers are mostly caught up you will see no read
> activity on the disks whatsoever as they will be serving data entirely
> from cache.
>
> However, when I ran tracing on all my kafka brokers, I didn't get a
> single sendfile system call, why his discrepancy?
>
> sudo ./syscount -p 126806 -d 30
> Tracing syscalls, printing top 10... Ctrl+C to quit.
> [17:44:10]
> SYSCALL COUNT
> epoll_wait 108482
> write 107165
> epoll_ctl 95058
> futex 86716
> read 86388
> pread 26910
> fstat 9213
> getrusage 120
> close 27
> open 21
>


--
-- Guozhang