lkml.org 
[lkml]   [2018]   [Aug]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRE: [PATCH 1/1] selftest/net: fix FILE_SIZE for 32 bit architecture.
From
Date
Hi,

>On 08/02/2018 03:31 AM, Maninder Singh wrote:
>> FILE_SZ is defined as (1UL << 35), it will overflow
>> for 32 bit system and logic will break.
>>
>> Signed-off-by: Maninder Singh <maninder1.s@samsung.com>
>> Signed-off-by: Vaneet Narang <v.narang@samsung.com>
>> ---
>> tools/testing/selftests/net/tcp_mmap.c | 8 ++++----
>> 1 file changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/tools/testing/selftests/net/tcp_mmap.c b/tools/testing/selftests/net/tcp_mmap.c
>> index e8c5dff..1d6ca12 100644
>> --- a/tools/testing/selftests/net/tcp_mmap.c
>> +++ b/tools/testing/selftests/net/tcp_mmap.c
>> @@ -85,7 +85,7 @@
>> #define MSG_ZEROCOPY 0x4000000
>> #endif
>>
>> -#define FILE_SZ (1UL << 35)
>> +#define FILE_SZ (1ULL << 35)

...
...
>> @@ -431,7 +431,7 @@ int main(int argc, char *argv[])
>> zflg = 0;
>> }
>> while (total < FILE_SZ) {
>> - long wr = FILE_SZ - total;
>> + unsigned long long wr = FILE_SZ - total;
>>
>> if (wr > chunk_size)
>> wr = chunk_size;
>>
>
>What about using more conventional size_t instead of "unsigned long long" ?

size_t is also equivalent to unsigned long and it will not hold value of (1 << 35) for 32 bit system.
So we can do two things.

(1) reduce FILE SIZE to (1 << 30), so that UL (size_t) can hold this value.
It will not show any perofrmance boost with ZEROCOPY. (checked on x86_64)

(2) use unsigned long long to work with both 32 and 64 bit system.
It will show performance boost with ZEROCOPY.(checked on x86_64)

What do you think?

Thanks and regards,
Maninder Singh

\
 
 \ /
  Last update: 2018-08-03 05:40    [W:0.052 / U:4.424 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site