Re: [jetty-user] 回复： [jetty-user] why jetty7 i s slower than jetty6?

Kafka,

that 998ms is very suspiciously close to 1s.  It looks like a write is
getting lost somehow and only unblocked as the selector wakes up.

I'll try to replicate this, but I need some more information.   Can
you capture the headers at the start of a response.   How frequently
do you send a 1M lump?  how long are the pauses between?   Can you
measure how much time each write takes (and the size of the byte array
written) plus the time the flush takes.

I'd also consider not flushing in the loop - but that should not cause
the 1s delay.

Note also, while we do need to find/fix this issue, there are much
much better ways of writing large data that will give you much better
performance and use a lot less memory.   It looks like your data is
coming from a file, so you really want to let jetty use NIO file
mapping to send the content and you typically will get a 10x
improvement in data rate plus no use space buffers are needed.     The
down side is that you can't use a long held request and stream out
data over time - you will have to send 1 file per response.  But you
can long poll and hold onto a request while waiting for a file to be
ready to be sent, and then let the default servlet send it.        I
think the way you have written your writer, the data is probably being
copied File system to Buffer, Buffer to byte array, byte array to
jetty buffer, jetty buffer to OS Buffer, OS Buffer to network
interface.   If you can arrange to use NIO file mapped buffers, then
the data will be copied File system to network interface.

But none the less.... I think there is a bug we need to fix.

cheers










2010/11/13 kafka0102 <[email protected]>:
> thanks for reply.
> I tried jetty-distribution-7.2.1.v20101111,  but it still had poor
> performance for solr's replication like 7.1.6.v20100715. I embed jetty
> 6.1.25(maven) to get great performance.I can give some solr's replication
> codes. For master's write, it's like:
>
> public void write(final OutputStream out) throws IOException {
>       final String fileName = params.get(FILE);
>       final String cfileName = params.get(CONF_FILE_SHORT);
>       final String sOffset = params.get(OFFSET);
>       final String sLen = params.get(LEN);
>       final String compress = params.get(COMPRESSION);
>       final String sChecksum = params.get(CHECKSUM);
>       final String sindexVersion = params.get(CMD_INDEX_VERSION);
>       if (sindexVersion != null) {
>         indexVersion = Long.parseLong(sindexVersion);
>       }
>       if (Boolean.parseBoolean(compress)) {
>         fos = new FastOutputStream(new DeflaterOutputStream(out));
>       } else {
>         fos = new FastOutputStream(out);
>       }
>       FileInputStream inputStream = null;
>       int packetsWritten = 0;
>       try {
>         long offset = -1;
>         int len = -1;
>         //check if checksum is requested
>         final boolean useChecksum = Boolean.parseBoolean(sChecksum);
>         if (sOffset != null) {
>           offset = Long.parseLong(sOffset);
>         }
>         if (sLen != null) {
>           len = Integer.parseInt(sLen);
>         }
>         if (fileName == null && cfileName == null) {
>           //no filename do nothing
>           writeNothing();
>         }
>
>         File file = null;
>         if (cfileName != null) {
>           //if if is a conf file read from config diectory
>           file = new File(core.getResourceLoader().getConfigDir(),
> cfileName);
>         } else {
>           //else read from the indexdirectory
>           file = new File(core.getIndexDir(), fileName);
>         }
>         if (file.exists() && file.canRead()) {
>           inputStream = new FileInputStream(file);
>           final FileChannel channel = inputStream.getChannel();
>           //if offset is mentioned move the pointer to that point
>           if (offset != -1) {
>             channel.position(offset);
>           }
>           final byte[] buf = new byte[len == -1 || len > PACKET_SZ ?
> PACKET_SZ : len];
>           Checksum checksum = null;
>           if (useChecksum) {
>             checksum = new Adler32();
>           }
>           final ByteBuffer bb = ByteBuffer.wrap(buf);
>
>           while (true) {
>             bb.clear();
>             final long bytesRead = channel.read(bb);
>             if (bytesRead <= 0) {
>               writeNothing();
>               fos.close();
>               break;
>             }
>             fos.writeInt((int) bytesRead);
>             if (useChecksum) {
>               checksum.reset();
>               checksum.update(buf, 0, (int) bytesRead);
>               fos.writeLong(checksum.getValue());
>             }
>             //            final long startTime = System.currentTimeMillis();
>             fos.write(buf, 0, (int) bytesRead);
>             fos.flush();
>             //            LOG.info("write "+bytesRead+"
> cost:"+(System.currentTimeMillis() - startTime));
>             if (indexVersion != null && packetsWritten % 5 == 0) {
>               //after every 5 packets reserve the commitpoint for some time
>               delPolicy.setReserveDuration(indexVersion,
> reserveCommitDuration);
>             }
>             packetsWritten++;
>           }
>         } else {
>           writeNothing();
>         }
>       } catch (final IOException e) {
>         LOG.warn("Exception while writing response for params: " + params,
> e);
>       } finally {
>         IOUtils.closeQuietly(inputStream);
>       }
>     }
>
> for slave's read,it's like:
>
>  private int fetchPackets(final FastInputStream fis) throws Exception {
>       final byte[] intbytes = new byte[4];
>       final byte[] longbytes = new byte[8];
>       try {
>         while (true) {
>           if (stop) {
>             stop = false;
>             aborted = true;
>             throw new ReplicationHandlerException("User aborted
> replication");
>           }
>           long checkSumServer = -1;
>           fis.readFully(intbytes);
>           //read the size of the packet
>           final int packetSize = readInt(intbytes);
>           if (packetSize <= 0) {
>             LOG.warn("No content recieved for file: " + currentFile);
>             return NO_CONTENT;
>           }
>           if (buf.length < packetSize) {
>             buf = new byte[packetSize];
>           }
>           if (checksum != null) {
>             //read the checksum
>             fis.readFully(longbytes);
>             checkSumServer = readLong(longbytes);
>           }
>           //then read the packet of bytes
>           final long startTime = System.currentTimeMillis();
>           fis.readFully(buf, 0, packetSize);
>           //          LOG.info("readFully"+packetSize+" cost " +
> (System.currentTimeMillis() - startTime));
>           //compare the checksum as sent from the master
>           if (includeChecksum) {
>             checksum.reset();
>             checksum.update(buf, 0, packetSize);
>             final long checkSumClient = checksum.getValue();
>             if (checkSumClient != checkSumServer) {
>               LOG.error("Checksum not matched between client and server for:
> " + currentFile);
>               //if checksum is wrong it is a problem return for retry
>               return 1;
>             }
>           }
>           //if everything is fine, write down the packet to the file
>           fileChannel.write(ByteBuffer.wrap(buf, 0, packetSize));
>           bytesDownloaded += packetSize;
>           if (bytesDownloaded >= size) {
>             return 0;
>           }
>           //errorcount is always set to zero after a successful packet
>           errorCount = 0;
>         }
>       } catch (final ReplicationHandlerException e) {
>         throw e;
>       } catch (final Exception e) {
>         LOG.warn("Error in fetching packets ", e);
>         //for any failure , increment the error count
>         errorCount++;
>         //if it fails for the same pacaket for   MAX_RETRIES fail and come
> out
>         if (errorCount > MAX_RETRIES) {
>           throw new SolrException(SolrException.ErrorCode.SERVER_ERROR,
>               "Fetch failed for file:" + fileName, e);
>         }
>         return ERR;
>       }
>     }
>
> solr writes PACKET_SZ(1M default) every time.I find one time is too
> slow(more than 900ms) every 3 times.When I change PACKET_SZ to 10M,it's
> about 3s every time.The effect is still like PACKET_SZ = 1M.
>
>
>
>
> ------------------ 原始邮件 ------------------
> 发件人: "Jesse McConnell"<[email protected]>;
> 发送时间: 2010年11月12日(星期五) 晚上9:53
> 收件人: "user"<[email protected]>;
> 主题: Re: [jetty-user] why jetty7 is slower than jetty6?
>
> which version of jetty?  we have resolved an issue that might apply to
> your case were performance was reduced, its resolved in the staged
> 7.2.1.v20101111 build that we'll likely promote soon..
>
> you can try it at:
>
> https://oss.sonatype.org/content/repositories/jetty-024/org/eclipse/jetty/jetty-distribution/7.2.1.v20101111/
>
> cheers,
> jesse
>
> --
> jesse mcconnell
> [email protected]
>
>
>
> On Fri, Nov 12, 2010 at 05:13, kafka0102 <[email protected]> wrote:
>> I use jetty as a web server for solr, and I find a problem. solr replicate
>> data from master to slave, and master uses a long http connection to write
>> data 1M every time.I print the time cost every 1M transit, and find
>> default's jetty7 cost is like 996ms,5ms,6ms,998ms,4ms,8ms,thus one time
>> cost
>> about 1s every 3 times. If I change to jetty6,it's so fast, and every time
>> just cost less then 1ms.For jetty6 and jetty7,I just use default's conf,
>> and
>> the problem consist in both embed and external jetty . Who can tell me
>> what
>> I'm wrong?
>>
>
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