[dpdk-dev] [PATCH] eal: avoid unnecessary conflicts over rte_config file
Ferruh Yigit
ferruh.yigit at intel.com
Fri Jan 11 22:52:51 CET 2019
On 10/14/2016 5:27 PM, ouster at cs.stanford.edu (John Ousterhout) wrote:
> It sounds like my patch would break some existing software, so it probably
> doesn't make sense right now.
>
> I'd still argue that the current mechanism has a number of problems, and it
> should probably undergo a comprehensive overhaul at some point in the
> future.
Hi John,
It seems there weren't any conclusion on the patch and it is sitting on
patchwork more than two years, I am updating it as rejected, if
it is still relevant please let us know.
Sorry for any inconvenience caused.
For record, patch: https://patches.dpdk.org/patch/16527/
Regards,
ferruh
>
> -John-
>
> On Thu, Oct 13, 2016 at 2:39 PM, Tahhan, Maryam <maryam.tahhan at intel.com>
> wrote:
>
>>> Hi John,
>>>
>>>> Before this patch, DPDK used the file ~/.rte_config as a lock to
>>>> detect potential interference between multiple DPDK applications
>>>> running on the same machine. However, if a single user ran DPDK
>>>> applications concurrently on several different machines, and if the
>>>> user's home directory was shared between the machines via NFS, DPDK
>>>> would incorrectly detect conflicts for all but the first application
>>>> and abort them. This patch fixes the problem by incorporating the
>>>> machine name into the config file name (e.g., ~/.rte_hostname_config).
>>>>
>>>> Signed-off-by: John Ousterhout <ouster at cs.stanford.edu>
>>>> ---
>>>> doc/guides/prog_guide/multi_proc_support.rst | 11 +++++++----
>>>> lib/librte_eal/common/eal_common_proc.c | 8 ++------
>>>> lib/librte_eal/common/eal_filesystem.h | 15 +++++++++++++--
>>>> 3 files changed, 22 insertions(+), 12 deletions(-)
>>>>
>>>> diff --git a/doc/guides/prog_guide/multi_proc_support.rst
>>>> b/doc/guides/prog_guide/multi_proc_support.rst
>>>> index badd102..a54fa1c 100644
>>>> --- a/doc/guides/prog_guide/multi_proc_support.rst
>>>> +++ b/doc/guides/prog_guide/multi_proc_support.rst
>>>> @@ -129,10 +129,13 @@ Support for this usage scenario is provided
>>>> using the ``--file-prefix`` paramete
>>>>
>>>> By default, the EAL creates hugepage files on each hugetlbfs
>>>> filesystem using the rtemap_X filename, where X is in the range 0 to
>> the
>>> maximum number of hugepages -1.
>>>> -Similarly, it creates shared configuration files, memory mapped in
>>>> each process, using the /var/run/.rte_config filename, -when run as
>>>> root (or $HOME/.rte_config when run as a non-root user; -if filesystem
>> and
>>> device permissions are set up to allow this).
>>>> -The rte part of the filenames of each of the above is configurable
>> using the
>>> file-prefix parameter.
>>>> +Similarly, it creates shared configuration files, memory mapped in
>> each
>>> process.
>>>> +When run as root, the name of the configuration file will be
>>>> +/var/run/.rte_*host*_config, where *host* is the name of the machine.
>>>> +When run as a non-root user, the the name of the configuration file
>>>> +will be $HOME/.rte_*host*_config (if filesystem and device permissions
>>> are set up to allow this).
>>>> +If the ``--file-prefix`` parameter has been specified, its value will
>>>> +be used in place of "rte" in the file names.
>>>
>>> I am not sure that we need to handle all such cases inside EAL.
>>> User can easily overcome that problem by just adding something like:
>>> --file-prefix=`uname -n`
>>> to his command-line.
>>> Konstantin
>>>
>>
>> I agree with Konstantin, there's no need to include the hostname in the
>> rte config file + I'm not sure this will be backward compatible with
>> existing DPDK applications that use a secondary processes that use the
>> config file (as in, multiprocess DPDK applications in use would all need to
>> be updated). What Konstantin suggests fixes the issue you were encountering
>> without breaking backward compatibility.
>> Is addition, the hostname is not unique... you could in theory have 2
>> hosts with the same hostname and encounter the issue you were seeing again.
>>
>>>>
>>>> In addition to specifying the file-prefix parameter, any DPDK
>>>> applications that are to be run side-by-side must explicitly limit
>> their
>>> memory use.
>>>> diff --git a/lib/librte_eal/common/eal_common_proc.c
>>>> b/lib/librte_eal/common/eal_common_proc.c
>>>> index 12e0fca..517aa0c 100644
>>>> --- a/lib/librte_eal/common/eal_common_proc.c
>>>> +++ b/lib/librte_eal/common/eal_common_proc.c
>>>> @@ -45,12 +45,8 @@ rte_eal_primary_proc_alive(const char
>>>> *config_file_path)
>>>>
>>>> if (config_file_path)
>>>> config_fd = open(config_file_path, O_RDONLY);
>>>> - else {
>>>> - char default_path[PATH_MAX+1];
>>>> - snprintf(default_path, PATH_MAX, RUNTIME_CONFIG_FMT,
>>>> - default_config_dir, "rte");
>>>> - config_fd = open(default_path, O_RDONLY);
>>>> - }
>>>> + else
>>>> + config_fd = open(eal_runtime_config_path(), O_RDONLY);
>>>> if (config_fd < 0)
>>>> return 0;
>>>>
>>>> diff --git a/lib/librte_eal/common/eal_filesystem.h
>>>> b/lib/librte_eal/common/eal_filesystem.h
>>>> index fdb4a70..4929aa3 100644
>>>> --- a/lib/librte_eal/common/eal_filesystem.h
>>>> +++ b/lib/librte_eal/common/eal_filesystem.h
>>>> @@ -41,7 +41,7 @@
>>>> #define EAL_FILESYSTEM_H
>>>>
>>>> /** Path of rte config file. */
>>>> -#define RUNTIME_CONFIG_FMT "%s/.%s_config"
>>>> +#define RUNTIME_CONFIG_FMT "%s/.%s_%s_config"
>>>>
>>>> #include <stdint.h>
>>>> #include <limits.h>
>>>> @@ -59,11 +59,22 @@ eal_runtime_config_path(void)
>>>> static char buffer[PATH_MAX]; /* static so auto-zeroed */
>>>> const char *directory = default_config_dir;
>>>> const char *home_dir = getenv("HOME");
>>>> + static char nameBuffer[1000];
>>>> + int result;
>>>>
>>>> if (getuid() != 0 && home_dir != NULL)
>>>> directory = home_dir;
>>>> +
>>>> + /*
>>>> + * Include the name of the host in the config file path. Otherwise,
>>>> + * if DPDK applications run on different hosts but share a home
>>>> + * directory (e.g. via NFS), they will choose the same config
>>>> + * file and conflict unnecessarily.
>>>> + */
>>>> + result = gethostname(nameBuffer, sizeof(nameBuffer)-1);
>>>> snprintf(buffer, sizeof(buffer) - 1, RUNTIME_CONFIG_FMT,
>>> directory,
>>>> - internal_config.hugefile_prefix);
>>>> + internal_config.hugefile_prefix,
>>>> + (result == 0) ? nameBuffer : "unknown-host");
>>>> return buffer;
>>>> }
>>>>
>>>> --
>>>> 2.8.3
>>
>>
>
More information about the dev
mailing list