With symbols going though experimental/stable stages, we accumulated
a lot of discrepancies about inclusion of the rte_compat.h header.
Some headers are including it where unneeded, while others rely on
implicit inclusion.
Fix unneeded inclusions:
$ git grep -l include..rte_compat.h |
xargs grep -LE '__rte_(internal|experimental)' |
xargs sed -i -e '/#include..rte_compat.h/d'
Fix missing inclusion, by inserting rte_compat.h before the first
inclusion of a DPDK header:
$ git grep -lE '__rte_(internal|experimental)' |
xargs grep -L include..rte_compat.h |
xargs sed -i -e \
'0,/#include..\(rte_\|.*pmd.h.$\)/{
s/\(#include..\(rte_\|.*pmd.h.$\)\)/#include <rte_compat.h>\n\1/
}'
Fix missing inclusion, by inserting rte_compat.h after the last
inclusion of a non DPDK header:
$ for file in $(git grep -lE '__rte_(internal|experimental)' |
xargs grep -L include..rte_compat.h); do
tac $file > $file.$$
sed -i -e \
'0,/#include../{
s/\(#include..*$\)/#include <rte_compat.h>\n\n\1/
}' $file.$$
tac $file.$$ > $file
rm $file.$$
done
Fix missing inclusion, by inserting rte_compat.h after the header guard:
$ git grep -lE '__rte_(internal|experimental)' |
xargs grep -L include..rte_compat.h |
xargs sed -i -e \
'0,/#define/{
s/\(#define .*$\)/\1\n\n#include <rte_compat.h>/
}'
And finally, exclude rte_compat.h itself.
$ git checkout lib/eal/include/rte_compat.h
At the end of all this, we have a clean tree:
$ git grep -lE '__rte_(internal|experimental)' |
xargs grep -L include..rte_compat.h
buildtools/check-symbols.sh
devtools/checkpatches.sh
doc/guides/contributing/abi_policy.rst
doc/guides/rel_notes/release_20_11.rst
lib/eal/include/rte_compat.h
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
When built with stats enabled (RTE_LIBRTE_MEMPOOL_STATS defined),
the performance of mempools with caches is improved as follows.
When accessing objects in the mempool, either the put_bulk and put_objs or
the get_success_bulk and get_success_objs statistics counters are likely
to be incremented.
By adding an alternative set of these counters to the mempool cache
structure, accessing the dedicated statistics structure is avoided
in the likely cases where these counters are incremented.
The trick here is that the cache line holding the mempool cache structure
is accessed anyway, in order to access the 'len' or 'flushthresh' fields.
Updating some statistics counters in the same cache line has lower
performance cost than accessing the statistics counters in the dedicated
statistics structure, which resides in another cache line.
mempool_perf_autotest with this patch shows the following improvements in
rate_persec.
The cost of enabling mempool stats (without debug) after this patch:
-6.8 % and -6.7 %, respectively without and with cache.
Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>
This patch adds statistics for unregistered non-EAL threads,
which was previously not included in the statistics.
Add one more entry to the stats array,
and use the last index for unregistered non-EAL threads.
The unregistered non-EAL thread statistics are incremented atomically.
In theory, the EAL thread counters should also be accessed atomically to
avoid tearing on 32 bit architectures. However, it was decided to avoid
the performance cost of using atomic operations, because:
1. these are debug counters, and
2. statistics counters in DPDK are usually incremented non-atomically.
Suggested-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>
Split stats from debug, to make mempool statistics available without the
performance cost of continuously validating the debug cookies in the
mempool elements.
mempool_perf_autotest shows the following improvements in rate_persec.
The cost of enabling mempool debug without this patch:
-28.1 % and -74.0 %, respectively without and with cache.
The cost of enabling mempool stats (without debug) after this patch:
-5.8 % and -21.2 %, respectively without and with cache.
Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
Acked-by: Konstantin Ananyev <konstantin.ananyev@huawei.com>
The cache was still full after flushing. In the opposite direction,
i.e. when getting objects from the cache, the cache is refilled to full
level when it crosses the low watermark (which happens to be zero).
Similarly, the cache should be flushed to empty level when it crosses
the high watermark (which happens to be 1.5 x the size of the cache).
The existing flushing behaviour was suboptimal for real applications,
because crossing the low or high watermark typically happens when the
application is in a state where the number of put/get events are out of
balance, e.g. when absorbing a burst of packets into a QoS queue
(getting more mbufs from the mempool), or when a burst of packets is
trickling out from the QoS queue (putting the mbufs back into the
mempool).
Now, the mempool cache is completely flushed when crossing the flush
threshold, so only the newly put (hot) objects remain in the mempool
cache afterwards.
This bug degraded performance caused by too frequent flushing.
Consider this application scenario:
Either, an lcore thread in the application is in a state of balance,
where it uses the mempool cache within its flush/refill boundaries; in
this situation, the flush method is less important, and this fix is
irrelevant.
Or, an lcore thread in the application is out of balance (either
permanently or temporarily), and mostly gets or puts objects from/to the
mempool. If it mostly puts objects, not flushing all of the objects will
cause more frequent flushing. This is the scenario addressed by this
fix. E.g.:
Cache size=256, flushthresh=384 (1.5x size), initial len=256;
application burst len=32.
If there are "size" objects in the cache after flushing, the cache is
flushed at every 4th burst.
If the cache is flushed completely, the cache is only flushed at every
16th burst.
As you can see, this bug caused the cache to be flushed 4x too
frequently in this example.
And when/if the application thread breaks its pattern of continuously
putting objects, and suddenly starts to get objects instead, it will
either get objects already in the cache, or the get() function will
refill the cache.
The concept of not flushing the cache completely was probably based on
an assumption that it is more likely for an application's lcore thread
to get() after flushing than to put() after flushing.
I strongly disagree with this assumption! If an application thread is
continuously putting so much that it overflows the cache, it is much
more likely to keep putting than it is to start getting. If in doubt,
consider how CPU branch predictors work: When the application has done
something many times consecutively, the branch predictor will expect the
application to do the same again, rather than suddenly do something
else.
Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Fix the rte_mempool_do_generic_put() caching flushing algorithm to
keep hot objects in cache instead of cold ones.
The algorithm was:
1. Add the objects to the cache.
2. Anything greater than the cache size (if it crosses the cache flush
threshold) is flushed to the backend.
Please note that the description in the source code said that it kept
"cache min value" objects after flushing, but the function actually kept
the cache full after flushing, which the above description reflects.
Now, the algorithm is:
1. If the objects cannot be added to the cache without crossing the
flush threshold, flush some cached objects to the backend to
free up required space.
2. Add the objects to the cache.
The most recent (hot) objects were flushed, leaving the oldest (cold)
objects in the mempool cache. The bug degraded performance, because
flushing prevented immediate reuse of the (hot) objects already in
the CPU cache. Now, the existing (cold) objects in the mempool cache
are flushed before the new (hot) objects are added the to the mempool
cache.
Since nearby code is touched anyway fix flush threshold comparison
to do flushing if the threshold is really exceed, not just reached.
I.e. it must be "len > flushthresh", not "len >= flushthresh".
Consider a flush multiplier of 1 instead of 1.5; the cache would be
flushed already when reaching size objects, not when exceeding size
objects. In other words, the cache would not be able to hold "size"
objects, which is clearly a bug. The bug could degraded performance
due to premature flushing.
Since we never exceed flush threshold now, cache size in the mempool
may be decreased from RTE_MEMPOOL_CACHE_MAX_SIZE * 3 to
RTE_MEMPOOL_CACHE_MAX_SIZE * 2. In fact it could be
CALC_CACHE_FLUSHTHRESH(RTE_MEMPOOL_CACHE_MAX_SIZE), but flush
threshold multiplier is internal.
Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Morten Brørup <mb@smartsharesystems.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Term ring is misleading since it is the default,
but still just one of possible drivers to store objects.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Morten Brørup <mb@smartsharesystems.com>
Enqueue operation must not fail. Move corresponding debug check
from one particular case to dequeue operation helper in order
to do it for all invocations.
Log critical message with useful information instead of rte_panic().
Make rte_mempool_do_generic_put() implementation more readable and
fix incosistency when return value is not checked in one place and
checked in another.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Morten Brørup <mb@smartsharesystems.com>
Callbacks for mempool events were registered in a process-shared tailq.
This was inherently incorrect because the same function
may be loaded to a different address in each process.
Make the tailq process-private.
Use the EAL tailq lock to reduce the number of different locks
this module operates.
Fixes: da2b9cb25e ("mempool: add event callbacks")
Cc: stable@dpdk.org
Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
A flush threshold for the mempool cache was introduced in DPDK version
1.3, but rte_mempool_do_generic_get() was not completely updated back
then, and some inefficiencies were introduced.
Fix the following in rte_mempool_do_generic_get():
1. The code that initially screens the cache request was not updated
with the change in DPDK version 1.3.
The initial screening compared the request length to the cache size,
which was correct before, but became irrelevant with the introduction of
the flush threshold. E.g. the cache can hold up to flushthresh objects,
which is more than its size, so some requests were not served from the
cache, even though they could be.
The initial screening has now been corrected to match the initial
screening in rte_mempool_do_generic_put(), which verifies that a cache
is present, and that the length of the request does not overflow the
memory allocated for the cache.
This bug caused a major performance degradation in scenarios where the
application burst length is the same as the cache size. In such cases,
the objects were not ever fetched from the mempool cache, regardless if
they could have been.
This scenario occurs e.g. if an application has configured a mempool
with a size matching the application's burst size.
2. The function is a helper for rte_mempool_generic_get(), so it must
behave according to the description of that function.
Specifically, objects must first be returned from the cache,
subsequently from the backend.
After the change in DPDK version 1.3, this was not the behavior when
the request was partially satisfied from the cache; instead, the objects
from the backend were returned ahead of the objects from the cache.
This bug degraded application performance on CPUs with a small L1 cache,
which benefit from having the hot objects first in the returned array.
(This is probably also the reason why the function returns the objects
in reverse order, which it still does.)
Now, all code paths first return objects from the cache, subsequently
from the backend.
The function was not behaving as described (by the function using it)
and expected by applications using it. This in itself is also a bug.
3. If the cache could not be backfilled, the function would attempt
to get all the requested objects from the backend (instead of only the
number of requested objects minus the objects available in the backend),
and the function would fail if that failed.
Now, the first part of the request is always satisfied from the cache,
and if the subsequent backfilling of the cache from the backend fails,
only the remaining requested objects are retrieved from the backend.
The function would fail despite there are enough objects in the cache
plus the common pool.
4. The code flow for satisfying the request from the cache was slightly
inefficient:
The likely code path where the objects are simply served from the cache
was treated as unlikely. Now it is treated as likely.
Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: Morten Brørup <mb@smartsharesystems.com>
Since 10 years, memzone allocation is allowed on secondary
processes. Now it's time to update the documentation accordingly.
At the same time, fix mempool, mbuf and ring documentation which rely on
memzones internally.
Bugzilla ID: 1074
Fixes: 916e4f4f4e ("memory: fix for multi process support")
Cc: stable@dpdk.org
Signed-off-by: Olivier Matz <olivier.matz@6wind.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
MEMPOOL_PG_NUM_DEFAULT and MEMPOOL_PG_SHIFT_MAX defines are unused
since xmem API removal.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: David Marchand <david.marchand@redhat.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Replacement RTE_MEMPOOL_REGISTER_OPS() should be used instead.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: David Marchand <david.marchand@redhat.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
MEMPOOL_HEADER_SIZE() is removed. The replacement with RTE_ prefix
is internal only since it is implementation details which are not
required in applications.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: David Marchand <david.marchand@redhat.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Make rte_driver opaque for non internal users.
This will make extending this object possible without breaking the ABI.
Introduce a new driver header and move rte_driver definition.
Update drivers and library to use the internal header.
Some applications may have been dereferencing rte_driver objects, mark
this object's accessors as stable.
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Bruce Richardson <bruce.richardson@intel.com>
Acked-by: Jay Jayatheerthan <jay.jayatheerthan@intel.com>
Acked-by: Ajit Khaparde <ajit.khaparde@broadcom.com>
Acked-by: Akhil Goyal <gakhil@marvell.com>
Acked-by: Abhinandan Gujjar <abhinandan.gujjar@intel.com>
Those macros have no real value and are easily replaced with a simple
if() block.
Existing users have been converted using a new cocci script.
Deprecate them.
Signed-off-by: David Marchand <david.marchand@redhat.com>
Start a new release cycle with empty release notes.
The ABI version becomes 23.0.
The map files are updated to the new ABI major number (23).
The ABI exceptions are dropped and CI ABI checks are disabled because
compatibility is not preserved.
Special handling of removed drivers is also dropped in check-abi.sh and
a note has been added in libabigail.abignore as a reminder.
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Thomas Monjalon <thomas@monjalon.net>
These functions all behave like libc free() and do
nothing if handed a NULL pointer. The code is already doing
this, this patch just documents the behavior.
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
When mempool had been created with RTE_MEMPOOL_F_NO_IOVA_CONTIG flag
but later populated with valid IOVA, RTE_MEMPOOL_F_NON_IO was unset,
while it should be kept. The unit test did not catch this
because rte_mempool_populate_default() it used was populating
with RTE_BAD_IOVA.
Keep setting RTE_MEMPOOL_NON_IO at an empty mempool creation
and add an assert for it in the unit test (remove the separate case).
Do not reset the flag if RTE_MEMPOOL_F_ON_IOVA_CONTIG is set.
Fixes: 11541c5c81 ("mempool: add non-IO flag")
Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
As reported by Dmitry, RTE_MEMPOOL_F_POOL_CREATED is a flag only
manipulated internally.
This flag is not supposed to be requested from an application and would
probably result in an incorrect behavior if an application did pass it.
At least one other internal flag has been added recently and more may be
introduced later.
Rework the check and export a mask of valid user flags for use in the
unit test.
Fixes: b240af8b10 ("mempool: enforce valid flags at creation")
Reported-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Signed-off-by: David Marchand <david.marchand@redhat.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
MEMPOOL_PG_NUM_DEFAULT and MEMPOOL_PG_SHIFT_MAX are not used.
Fixes: fd943c764a ("mempool: deprecate xmem functions")
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Add RTE_ prefix to macro used to register mempool driver.
The old one is still available but deprecated.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Add RTE_ prefix to helper macro to calculate mempool header size and
make it internal. Old macro is still available, but deprecated.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Add RTE_ prefix to internal API defined in public header.
Use the prefix instead of double underscore.
Use uppercase for macros in the case of name conflict.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Fix the mempool flags namespace by adding an RTE_ prefix to the name.
The old flags remain usable, to be deprecated in the future.
Flag MEMPOOL_F_NON_IO added in the release is just renamed to have RTE_
prefix.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Move documentation into a separate line just before define.
Prepare to have a bit longer flag name because of namespace prefix.
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
Mempool is a generic allocator that is not necessarily used
for device IO operations and its memory for DMA.
Add MEMPOOL_F_NON_IO flag to mark such mempools automatically
a) if their objects are not contiguous;
b) if IOVA is not available for any object.
Other components can inspect this flag
in order to optimize their memory management.
Discussion: https://mails.dpdk.org/archives/dev/2021-August/216654.html
Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Data path performance can benefit if the PMD knows which memory it will
need to handle in advance, before the first mbuf is sent to the PMD.
It is impractical, however, to consider all allocated memory for this
purpose. Most often mbuf memory comes from mempools that can come and
go. PMD can enumerate existing mempools on device start, but it also
needs to track creation and destruction of mempools after the forwarding
starts but before an mbuf from the new mempool is sent to the device.
Add an API to register callback for mempool life cycle events:
* rte_mempool_event_callback_register()
* rte_mempool_event_callback_unregister()
Currently tracked events are:
* RTE_MEMPOOL_EVENT_READY (after populating a mempool)
* RTE_MEMPOOL_EVENT_DESTROY (before freeing a mempool)
Provide a unit test for the new API.
The new API is internal, because it is primarily demanded by PMDs that
may need to deal with any mempools and do not control their creation,
while an application, on the other hand, knows which mempools it creates
and doesn't care about internal mempools PMDs might create.
Signed-off-by: Dmitry Kozlyuk <dkozlyuk@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
If we do not enforce valid flags are passed by an application, this
application might face issues in the future when we add more flags.
Signed-off-by: David Marchand <david.marchand@redhat.com>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Acked-by: Ray Kinsella <mdr@ashroe.eu>
Acked-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Use correct define as a name array size.
The change breaks ABI and therefore cannot be backported to
stable branches.
Fixes: 38c9817ee1 ("mempool: adjust name size in related data types")
Signed-off-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Reviewed-by: David Marchand <david.marchand@redhat.com>
Currently there are some public headers that include 'sys/queue.h', which
is not POSIX, but usually provided by the Linux/BSD system library.
(Not in POSIX.1, POSIX.1-2001, or POSIX.1-2008. Present on the BSDs.)
The file is missing on Windows. During the Windows build, DPDK uses a
bundled copy, so building a DPDK library works fine. But when OVS or other
applications use DPDK as a library, because some DPDK public headers
include 'sys/queue.h', on Windows, it triggers an error due to no such
file.
One solution is to install the 'lib/eal/windows/include/sys/queue.h' into
Windows environment, such as [1]. However, this means DPDK exports the
functionalities of 'sys/queue.h' into the environment, which might cause
symbols, macros, headers clashing with other applications.
The patch fixes it by removing the "#include <sys/queue.h>" from
DPDK public headers, so programs including DPDK headers don't depend
on the system to provide 'sys/queue.h'. When these public headers use
macros such as TAILQ_xxx, we replace it by the ones with RTE_ prefix.
For Windows, we copy the definitions from <sys/queue.h> to rte_os.h
in Windows EAL. Note that these RTE_ macros are compatible with
<sys/queue.h>, both at the level of API (to use with <sys/queue.h>
macros in C files) and ABI (to avoid breaking it).
Additionally, the TAILQ_FOREACH_SAFE is not part of <sys/queue.h>,
the patch replaces it with RTE_TAILQ_FOREACH_SAFE.
[1] http://mails.dpdk.org/archives/dev/2021-August/216304.html
Suggested-by: Nick Connolly <nick.connolly@mayadata.io>
Suggested-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Signed-off-by: William Tu <u9012063@gmail.com>
Acked-by: Dmitry Kozlyuk <dmitry.kozliuk@gmail.com>
Acked-by: Narcisa Vasile <navasile@linux.microsoft.com>
Start a new release cycle with empty release notes.
The ABI version becomes 22.0.
The map files are updated to the new ABI major number (22).
The ABI exceptions are dropped and CI ABI checks are disabled because
compatibility is not preserved.
Signed-off-by: Thomas Monjalon <thomas@monjalon.net>
Acked-by: Ferruh Yigit <ferruh.yigit@intel.com>
Acked-by: David Marchand <david.marchand@redhat.com>
If cache is enabled, objects will be retrieved/put from/to cache,
subsequently from/to the common pool. Now the debug stats calculate
the objects retrieved/put from/to cache and pool together, it is
better to distinguish them.
Signed-off-by: Joyce Kong <joyce.kong@arm.com>
Signed-off-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Acked-by: Olivier Matz <olivier.matz@6wind.com>
There is no reason for the DPDK libraries to all have 'librte_' prefix on
the directory names. This prefix makes the directory names longer and also
makes it awkward to add features referring to individual libraries in the
build - should the lib names be specified with or without the prefix.
Therefore, we can just remove the library prefix and use the library's
unique name as the directory name, i.e. 'eal' rather than 'librte_eal'
Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
